Skip to main content
PLOS ONE logoLink to PLOS ONE
. 2021 May 27;16(5):e0247918. doi: 10.1371/journal.pone.0247918

The Abbott PanBio WHO emergency use listed, rapid, antigen-detecting point-of-care diagnostic test for SARS-CoV-2—Evaluation of the accuracy and ease-of-use

Lisa J Krüger 1, Mary Gaeddert 1, Frank Tobian 1, Federica Lainati 1, Claudius Gottschalk 1, Julian A F Klein 1, Paul Schnitzler 2, Hans-Georg Kräusslich 2, Olga Nikolai 3, Andreas K Lindner 3, Frank P Mockenhaupt 3, Joachim Seybold 4, Victor M Corman 5,6, Christian Drosten 5,6, Nira R Pollock 7, Britta Knorr 8, Andreas Welker 8, Margaretha de Vos 9, Jilian A Sacks 9, Claudia M Denkinger 1,10,*; for the study team
Editor: Nicholas J Mantis11
PMCID: PMC8158996  PMID: 34043631

Abstract

Objectives

Diagnostics are essential for controlling the pandemic. Identifying a reliable and fast diagnostic device is needed for effective testing. We assessed performance and ease-of-use of the Abbott PanBio antigen-detecting rapid diagnostic test (Ag-RDT).

Methods

This prospective, multi-centre diagnostic accuracy study enrolled at two sites in Germany. Following routine testing with reverse-transcriptase polymerase chain reaction (RT-PCR), a second study-exclusive swab was performed for Ag-RDT testing. Routine swabs were nasopharyngeal (NP) or combined NP/oropharyngeal (OP) whereas the study-exclusive swabs were NP. To evaluate performance, sensitivity and specificity were assessed overall and in predefined sub-analyses accordingly to cycle-threshold values, days after symptom onset, disease severity and study site. Additionally, an ease-of-use assessment (EoU) and System Usability Scale (SUS) were performed.

Results

1108 participants were enrolled between Sept 28 and Oct 30, 2020. Of these, 106 (9.6%) were PCR-positive. The Abbott PanBio detected 92/106 PCR-positive participants with a sensitivity of 86.8% (95% CI: 79.0% - 92.0%) and a specificity of 99.9% (95% CI: 99.4%-100%). The sub-analyses indicated that sensitivity was 95.8% in Ct-values <25 and within the first seven days from symptom onset. The test was characterized as easy to use (SUS: 86/100) and considered suitable for point-of-care settings.

Conclusion

The Abbott PanBio Ag-RDT performs well for SARS-CoV-2 testing in this large manufacturer independent study, confirming its WHO recommendation for Emergency Use in settings with limited resources.

Introduction

Diagnostics are a cornerstone of pandemic control. In March 2020, the World Health Organisation (WHO) emphasized the importance of access to testing for an effective control of SARS-CoV-2 infections [1]. While reverse-transcriptase polymerase chain reaction (RT-PCR) remains the gold standard among diagnostic tests for SARS-CoV-2, access may be limited due to shortages of instruments, supplies and experienced operators, particularly in resource-limited settings. Antigen-detecting tests (Ag-RDTs) offer an alternative to RT-PCR and have been recommended by the WHO for appropriate settings where nucleic acid amplification technology (NAAT) testing is limited or where prolonged turnaround times slow down clinical testing if they achieve at least ≥80% sensitivity and ≥97% specificity compared to a NAAT reference assay [2].

The Foundation of New Innovative Diagnostics (FIND) has identified >80 antigen tests in the pipeline for SARS-CoV-2 [3]. To this date, the WHO has recommended two Ag-RDTs on the Emergency Use Listing based on data from manufacturers as well as one independently-conducted accuracy study [4]. These two Ag-RDTs are SD Biosensor STANDARD Q (recommended on Sept 22, 2020) followed by the Abbott PanBio Ag-RDT (Oct 2,2020) [5, 6]. This manufacturer-independent study follows a WHO-approved protocol to complement the data provided to the WHO by the manufacturer.

Several other studies evaluating the Abbott PanBio Ag-RDT have been published to date. Of three large studies only one single-centre study prospectively enrolled participants [7]. The other two selected stored samples with the representativeness of the selection being unclear in one study [8, 9]. One study with a limited sample size (N = 255) concluded that sensitivity was the highest within the first week after symptom onset [10] supported by two additional studies reporting sensitivity to be the highest in participants presenting with a low Ct-value and a respectively high viral load, often observed at the onset of symptoms [11, 12]. The sensitivity was determined to be in the range of 60%-92% in these six studies along with a very high specificity of 98.9% and above [712].

The prospective multi-centre clinical accuracy study reported here, represents the largest manufacturer-independent dataset for the point-of-care (POC) performance of the Abbott PanBio Ag-RDT of date and also represents to our knowledge the only comprehensive ease-of-use assessment (EoU) of the Abbott PanBio Ag-RDT.

Material and methods

Ethic statement

The study protocol was approved in March 2020 by the ethical review committee at the Heidelberg University Hospital for the two study sites Heidelberg and Berlin in Germany (Registration number S-180/2020).

Clinical diagnostic accuracy study

The standards for reporting diagnostic accuracy studies (STARD) were followed for this study.

The test evaluated in this accuracy study is the PanBio COVID-19 Ag Rapid Test Device (Abbott Rapid Diagnostics, Jena, Germany; henceforth called PanBio) [13].

The test uses the lateral flow assay principle in a cassette format design for the detection of viral antigens. The test kits include proprietary swabs for sample collection. As indicated in the instruction for use (IFU), five drops of the extracted specimen in the provided buffer solution are applied to the test device. Colloidal gold conjugated antibodies on the membrane strip react with viral antigens generating a colour change in the device window, which can be interpreted with the naked eye. The results should be interpreted within 15 to 20 minutes of incubation and are considered invalid if interpreted after this timeframe. The manufacturer’s IFU were followed during sampling and testing procedures.

Study design and participants

The enrolment of participants was conducted at two sites in Germany; in Heidelberg at a drive-in testing site; in Berlin at a clinical ambulatory testing facility. Inclusion criteria for the participation were age ≥18 years and classification as being at risk for a SARS-CoV-2 infection by the local health department based on contact with a confirmed SARS-CoV-2 case or symptoms suggestive for infection. Individuals with a prior positive RT-PCR test for SARS-CoV-2 or those who could not give written informed consent due to limited command of English or German were excluded. The study protocol is available upon request.

Study procedures

Individuals meeting the inclusion criteria were invited to participate in the study. After providing written informed consent, participants first underwent the routine swab for RT-PCR testing directly followed by the study-exclusive swab for Ag-RDT testing, performed by the trained study team. Routine sampling for RT-PCR testing was performed with a nasopharyngeal (NP) swab in Heidelberg and a combination of a NP and oropharyngeal (OP) swab in Berlin as per institutional procedure. The study-exclusive sampling for the Ag-RDT PanBio was an NP swab. If NP swabbing was contraindicated for clinical reasons an OP swab was performed. The study-exclusive swab was taken in the same nostril as the routine swab. Laboratory personnel working in both the Ag-RDT testing team and the RT-PCR laboratory were blinded to the results of the other test at all times.

Antigen-detecting testing

Ag-RDT testing was performed in immediate proximity to the sampling in a separate room/container. The Ag-RDT test was started directly after sample collection. The test was conducted as indicated in the IFU, interpreting the test with the naked eye after 15 minutes by two readers blinded to the results of the other. In the case of discrepant results both readers re-interpreted the results and agreed on a final result. Invalid test results were repeated once with the remaining buffer solution in the test tubes.

RT-PCR testing

The collected swabs (Heidelberg, IMPROSWAB, Improve; Berlin, eSwab, Copan) for routine RT-PCR testing were kept in provided Amies solution. The RT-PCR assays performed were Allplex SARS-CoV-2 Assay from Seegene (Seoul, South Korea) in Heidelberg and the Roche cobas SARS CoV-2 assay (Pleasanton, CA United States) on the cobas® 6800 or 8800 system or the SARS CoV-2 assay from TibMolbiol (Berlin, Germany) in Berlin. Ct-values varied in a range of 2–3 between the three technologies. For the Ct-value presentation and the viral load calculations the E-Gene was used as reference Ct-value. A conversion of the Ct-values into viral-load was performed using quantified specific in vitro-transcribed RNA [14].

Additional data collection

All participants were asked to provide additional information about their comorbidities, symptoms, symptom duration and severity of disease (questionnaire available in the, Section (B) in S1 File).

Data management

All data were collected and managed using Research Electronic Data Capture (REDCap) tools hosted at Heidelberg University [15].

System usability scale and ease-of-use assessment

A standardized System Usability Scale (SUS) questionnaire and an ease-of-use assessment (EoU) were designed to understand the usability and feasibility of the test [16]. The questionnaire and the EoU survey can be found in the Section (C) and (D) in S1 File. Laboratory personnel from both study sites were invited to complete the questionnaire. An over-all SUS score above 68 is interpreted as above average and anything below the score of 68 is below average [16]. A heat-map was generated to analyse aspects related to the ease-of-use of the test, categorising each as satisfactory, average or dissatisfactory (Section (E) in S1 File and Fig 1). The matrix used for this analysis is also found in the Section (F) in S1 File.

Fig 1. Study flow.

Fig 1

Statistical analysis

The sensitivity and specificity of the Ag-RDT with 95% confidence intervals (95% CIs) were assessed as per Altman compared to RT-PCR as reference standard (sample size calculations are provided in the S1 File; a statistical analysis plan is available upon request) [17]. Sub-analyses were performed by sampling strategy, symptoms, duration of symptoms, Ct-values and study sites. The significance threshold was set at a two-sided alpha value of 0.05. Participants with an invalid PCR result were excluded from the analysis. All analyses and plots were performed using the R version 4.0.3.

Results

Clinical diagnostic accuracy

During the enrolment period, from Sept 28, 2020 to Oct 30, 2020, a total of 1261 eligible participants meeting the inclusion criteria were screened for this study. From these 1261 participants, 1119 agreed to undergo a second swab for study purposes only (Fig 1). 10 participants had to be excluded from the study, initially agreeing on participation but denying a second sample collection after the routine swab was performed. After the data cleaning and the exclusion of one invalid PCR test result (N = 1), a total of 1108 participants were included in the analysis. The site in Heidelberg enrolled 858 participants between the Sept 28 and Oct 30, 2020, and the site in Berlin enrolled 250 participants between Oct 19–30, 2020.

The clinical and demographic characteristics of the enrolled participants are summarized in Table 1. The mean age of all participants was 39.4 years (Standard Deviation (SD) 14.1) with Berlin presenting a younger study population compared to Heidelberg. 50.7% of participants were female and 33.4% had comorbidities. 712 participants (64.7%) reported having symptoms on the testing day, with an average symptom duration in days of 4.01 days (SD 3.1). The populations enrolled in Berlin and Heidelberg were significantly different in that participants in Berlin typically enrolled with symptoms (96.8%) while in Heidelberg almost half of the participants were tested based on high-risk contacts without symptoms and compared to the other half of participants reporting symptoms on the testing day (54.8%). Also, participants in Heidelberg were more likely to present earlier in their course of disease (mean 3.5 versus 4.98 days in Berlin) and were more likely to have comorbidities (36.6% in Heidelberg versus 21.2% in Berlin). In total 106 (9.6%) participants were diagnosed with a SARS-CoV-2 infection by RT-PCR testing during the enrolment period with 23.6% in Berlin and 5.5% in Heidelberg. The mean viral load was 7.4 for both sites with only a slight difference in the SD (Table 1).

Table 1. Study population characteristics.

Overall Total N = 1108 Heidelberg Total N = 858 Berlin Total N = 250
Age in years Information available on N = 1108 Mean (SD) 39.4 (14.1) 40.3 (14.6) 34.7 (11.5)
Gender Information available on N = 1099 Female N (%) 557 (50.7) 455 (53.0) 102 (40.8)
BMI >25 Information available on N = 1030 N (%) 487 (47.3) 424 (49.4) 63 (24.8)
Comorbidities Information available on N = 1100 N (%) 367 (33.4) 314 (36.6) 53 (21.2)
Symptoms on Testing Day Information available on N = 1100 N (%) 712 (64.7) 470 (54.8) 242 (96.8)
Duration of symptoms from day of testing in days Information available on N = 687 Mean (SD) 4.01 (3.1) 3.50 (2.83) 4.98 (3.32)
Previous test negative Information available on N = 885 Yes N (%) 250 (28.2) 217 (25.3) 33 (13.2)
RT-PCR positives N (%) 106 (9.6) 47 (5.5) 59 (23.6)
Viral Load (log10 SARS-CoV2 RNA copies/ml) Information available on N = 105* Mean (SD) 7.4 (1.4) 7.4 (1.3) 7.4 (1.5)

• One RT-PCR positive with a mutation in the E gene was excluded

The PanBio had an overall sensitivity of 86.8% (92/106 RT-PCR positives detected; 95% Confidence Interval (CI): 79.0% - 92.0%) and a specificity of 99.9% (1 false positive; 95% CI: 99.4%-100%). In a predefined sub analysis by Ct-value, sensitivity for samples that had a Ct-Value > = 25 was 66.7% (95% CI: 49.6%-80.2%) and sensitivity for samples with a Ct-value <25 was 95.8% (95% CI: 88.5%-98.6%). When samples with a Ct-value > = 30 were assessed, the sensitivity was only 33% (95% CI 13.8%-60.1%) but 93.5% (95% CI: 86.6%-97.0%) for samples with a Ct-value <30 (see Table 2 and Fig 2). The sensitivity decreased as viral load decreased (Fig 2). A detailed table summarizing the symptoms for Ag-RDT positive and negative participants, the viral load equivalents to the Ct-values and the RT-PCR reference standard is provided in the Section (G) and (H) in S1 File.

Table 2. Subgroup analyses for PanBio.

Overall N (%) Ag-Test positive/ PCR positive N (%) Ag-Test negative/ PCR positive N (%) Ag-Test positive/ PCR negative N (%) Ag-Test negative/ PCR negative N (%) Sensitivity % (95% CI) Specificity % (95% CI)
Sensitivity
Overall 1108 (100) 92 (8.3) 14 (1.3) 1 (0.1) 1001 (90.3) 86.8 (79.0–92.0) 99.9 (99.4–100)
Heidelberg 858 (77.4) 44 (5.1) 3 (0.3) 0 811 (94.5) 93.6 (82.8–97.8) 100 (99.5–100)
Berlin 250 (22.6) 48 (19.2) 11 (4.4) 1 (0.4) 190 (76.0) 81.4 (69.6–89.3) 99.5 (97.1–100)
Sampling strategy—Information available for N = 1108
NP swab 1034 (93.3) 91 (8.8) 13 (1.3) 1 (0.1) 929 (89.8) 87.5 (79.8–92.5) 99.9 (99.4–100)
OP swab 74 (6.7) 1 (1.4) 1 (1.4) 0 72 (97.3) 50.0 (25.6–97.4) 100 (94.9–100)
Symptom duration—Information available for N = 687
0–7 days Overall 610 (88.8) 69 (11.3) 7 (1.1) 1 (0.2) 533 (87.4) 90.8 (82.2–95.5) 99.6 (98.9–100)
8–14 days Overall 70 (10.2) 8 (11.4) 5 (7.1) 0 57 (81.4) 61.5 (35.5–82.3) 100 (93.7–100)
Symptomatic versus Asymptomatic—Information available for N = 1100
Symptomatic 712 (64.7) 79 (11.1) 12 (1.7) 1 (0.1) 620 (87.1) 86.8 (78.2–92.3) 99.8 (99.1–100)
Asymptomatic 388 (35.3) 12 (3.1) 2 (0.5) 0 374 (96.4) 85.7 (60.1–96∙0) 100 (99.0–100)
Ct-Value PCR <30 and > = 30—Information available for N = 105*
CT value PCR <30 93 (88) 87 (93.5) 6 (6.5) NA NA 93.5 (86.6–97.0) NA
CT value PCR > = 30 12 (11.0) 4 (33.0) 8 (67.0) NA NA 33 (13.8–60.1) NA
Ct-Value PCR <25 and > = 25—Information available for N = 105*
CT value PCR <25 72 (68.0) 69 (95.8) 3 (4.2) NA NA 95.8 (88.5–98.6) NA
CT value PCR > = 25 33 (31.0) 22 (66.7) 11 (33.3) NA NA 66.7 (49.6–80.2) NA

• One RT-PCR positive with a mutation in the E gene was excluded

Fig 2. Sensitivity of PanBio Ag-RDT compared to viral load for all PCR positive cases (105 participants).

Fig 2

When assessing test performance by duration of symptoms, we found PanBio performed well in the first 7 days after symptom onset (sensitivity 90.8% (95% CI: 82.2%-95.5%)), with declining sensitivity thereafter (>7 days of symptoms, sensitivity 61.5% (95% CI: 35.5%-82.3%)). This decrease in sensitivity with prolonged symptom duration is also shown in Fig 3, presenting the performance of PanBio with increasing days since symptom onset in relation to the calculated viral load for symptomatic and asymptomatic participants and the Ag-RDT performance.

Fig 3. Viral load and Ag-RDT results for asymptomatic participants and by days post symptom onset for all PCR positive cases (105 participants).

Fig 3

Out of the total 106 positive RT-PCR cases, 14 participants were without symptoms but with recent high-risk contacts. Within this small participant group the sensitivity of the Ag-RDT was 85.7% (60.1%-96.0%), which compares to the sensitivity of symptomatic participants at 86.8% (78.2%-92.3%); Table 2). Mean Ct-value in asymptomatic was 22.1 (SD 4.4) versus 23.1 (SD 5.0) in symptomatic participants.

The interrater reliability with kappa of 0.99 suggests that the tests results are clearly interpretable. PanBio scored 86 out of 100 points in the SUS showing a test which is easy to use. Problems were encountered when applying the exact amount of the required five drops to the test device (Section (E) in S1 File).

Discussion

This prospective multi-centre clinical diagnostic accuracy study shows that the PanBio Ag-RDT from Abbott has a good sensitivity of 86.8% and a very high specificity of 99.9% for symptomatic participants and participants with confirmed recent high-risk contacts compared to the reference standard RT-PCR. The Ag-RDT is easily performed in a point-of-care setting.

The differences observed in sensitivity between the two enrolment sites are probably explained by the different stages of the pandemic control. Berlin had a substantially higher prevalence with primarily symptomatic patients being tested and testing occurring later in the disease. Although the mean viral load was the same, the distribution of the viral load was not the same and more participants presented with low viral loads in Berlin, later in the course of infection. There were 15 patients presenting with viral loads <6 log10 copies/mL versus only 8 in Heidelberg. The samples with low viral loads, were responsible for 8 out of the 11 discordant results (false-negative) in Berlin, and 2 out of 3 in Heidelberg. Viral load dynamics play an important role in disease transmission, often rising before symptom onset with an observed peak at the time of symptom onset or at day 3–5 of the disease and a rapid decrease within the following days [18].

With a performance of 93.5% for CT value <30 and 90.8% within the first 7 days of symptoms, the test is likely to detect the vast majority of people with transmission potential SARS-CoV2 infections, supporting recent published literature [10, 19, 20]. These findings show that the PanBio Ag-RDT has a great potential in a public health setting, identifying the transmission relevant infections within the first 7 days of symptoms. Within the limitation of what can be concluded due to the small sample size of participants without symptoms at the time of testing and the fact that these participants were asymptomatic high-risk contacts presenting early in the disease, the performance of the test was as good as in symptomatic patients with a sensitivity respectively of 85.7% versus 86.8%. This suggests the PanBio to be an option for screening independent of symptoms, especially when the time of exposure is known and is supported by recent data suggesting that viral load in adults does not differ between asymptomatic and symptomatic infections [21].

Considering the test’s ease-of-use and the rapid turn-around time between 15 and 20 minutes, along with its high specificity, it could be considered for several use-cases: (1) screening in advance of events at high-risk of transmission (e.g. aggregated settings where contact cannot be avoided); or (2) necessary encounters with persons at high-risk for severe disease of SARS-CoV-2 (e.g. visitor in nursing homes) in addition to (3) the use in symptomatic patients within the first week of illness when RT-PCR is not available or together with RT-PCR, when a rapid decision is necessary.

Furthermore, given that supervised self-sampling from the anterior nose is a reliable alternative to professional nasopharyngeal sampling, scale-up of testing appears possible without requiring large numbers of trained health-care workers [22, 23].

Overall, our study has several strengths. The population enrolled for testing was representative of the pandemic observed in adults in Germany with a broad spectrum of clinical presentations (from asymptomatic with high-risk contacts to severely ill). Due to the wide-spread testing available and the good test and trace capabilities, the population tested is expected to be a representative spectrum of disease. Also, the tests were performed at POC thus mimicking the real-world challenges of POC testing. Lastly, the comprehensive ease-of-use assessment highlighted important points for operationalization of the test.

However, the study also has several limitations. First, it was conducted only in one country, thus making it less representative of the pandemic at large. Second, the reference standard testing was performed on an NP swab in Heidelberg versus an NP/OP swab in Berlin. However, a recent systematic review does not suggest those sampling methods to yield different results [24]. Thirdly, participants without symptoms at the time of testing could potentially have developed symptoms after being tested, yet this information was not recorded during this study. Furthermore, the time of exposure to high-risk contacts for participants without symptoms was not recorded, giving the possibility that these participants presented very early in the course of disease, maybe resulting in false-negatives [25]. And lastly, we performed different PCR methods as a reference standard recognizing the limitations of this method However, we aimed to provide comparability between methods by calibrating the methods and in addition reporting on viral load. Furthermore, we acknowledge the limitation of the PCR method as a reference standard, as it is not always a meaningful test when considering viable virus and risk of transmission [26]. Thus, using the PCR reference standard, we might have underestimated the performance of the Ag-RDT when it comes to detection of viable virus.

In summary, the favourable ease-of-use results and the limited infrastructure required for the Ag-RDT testing procedure, its high specificity in addition to the high sensitivity of the test in persons with high viral load, can empower control of population transmission if implemented in well-designed testing programs [2729]. Policy makers should move from considering only test sensitivity to more holistic testing strategies, incorporating Ag-RDTs in addition to and in combination with RT-PCR to optimize the reach and depth of testing.

Supporting information

S1 File

(DOCX)

Acknowledgments

We acknowledge the work of Angelika Sandritter in supporting the organisation and employees of this study. In addition, we thank the team of the KTS and the local Health Department Rhein-Neckar for their support on the testing site.

Data Availability

All relevant data are available at https://doi.org/10.11588/data/FSPQL4.

Funding Statement

The study was supported by Heidelberg and Charité University Hospital internal funds awarded to CD, as well as a grant of the Ministry of Science, Research and the Arts of Baden-Württemberg, Germany awarded to CD. Foundation of Innovative New Diagnostics (FIND) reports grants from UK Department of International Development (DFID, recently replaced by FCMO - UK Foreign, Commonwealth & Development Office) (Grant No. 300341-102) awarded to JS, grants from World Health Organization (WHO) awarded to JS, and grants from Unitaid (No. 2019-32-FIND MDR) awarded to JS to conduct of the study.

References

  • 1.World Health Organization. Director-General’s opening remarks at the media briefing on COVID-19: World Health Organization; 2020. [updated 16.03.202010.11.2020]. https://www.who.int/dg/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19—16-march-2020 [Google Scholar]
  • 2.World Health Organization. Antigendetection in the diagnosis of SARS-CoV-2 infection using rapid immunoassays—Interim Guidance https://www.who.int/publications/i/item/antigen-detection-in-the-diagnosis-of-sars-cov-2infection-using-rapid-immunoassays; 2020. 11.09.2020. [Google Scholar]
  • 3.Foundation of Innovative New Diagnsotics. SARS-CoV-2 diagnostic pipeline: Foundation of Innovative New Diagnostics 2020. [https://www.finddx.org/covid-19/pipeline/?avance=all&type=Rapid+diagnostic+tests&test_target=Antigen&status=all&section=show-all&action=default. [Google Scholar]
  • 4.Krüger LJ, Gaeddert M, Köppel L, Brümmer LE, Gottschalk C, Miranda IB, et al. Evaluation of the accuracy, ease of use and limit of detection of novel, rapid, antigen-detecting point-of-care diagnostics for SARS-CoV-2. medRxiv. 2020:2020. [Google Scholar]
  • 5.World Health Organisation. WHO Emergency Use Listing for In vitro diagnostics (IVDs) Detecting SARS-CoV-2. 2020. [Google Scholar]
  • 6.World Health Organisation. WHO Emergency Use Assessment Coronavirus disease (COVID-19) IVDs Public Report 2020. 10.2020. [Google Scholar]
  • 7.Berger A, Ngo Nsoga M-T, Perez Rodriguez FJ, Abi Aad Y, Sattonnet P, Gayet-Ageron A, et al. Diagnostic accuracy of two commercial SARS-CoV-2 Antigen-detecting rapid tests at the point of care in community-based testing centers. medRxiv. 2020:2020.11.20.20235341. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Alemany A, Baro B, Ouchi D, Ubals M, Corbacho-Monné M, Vergara-Alert J, et al. Analytical and Clinical Performance of the Panbio COVID-19 Antigen-Detecting Rapid Diagnostic Test. medRxiv. 2020:2020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Gremmels H, Winkel BMF, Schuurman R, Rosingh A, Rigter NAM, Rodriguez O, et al. Real-life validation of the Panbio COVID-19 Antigen Rapid Test (Abbott) in community-dwelling subjects with symptoms of potential SARS-CoV-2 infection. medRxiv. 2020:2020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Linares M, Pérez-Tanoira R, Carrero A, Romanyk J, Pérez-García F, Gómez-Herruz P, et al. Panbio antigen rapid test is reliable to diagnose SARS-CoV-2 infection in the first 7 days after the onset of symptoms. J Clin Virol. 2020;133:104659-. 10.1016/j.jcv.2020.104659 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Fenollar F, Bouam A, Ballouche M, Fuster L, Prudent E, Colson P, et al. Evaluation of the Panbio COVID-19 Rapid Antigen Detection Test Device for the Screening of Patients with COVID-19. Journal of Clinical Microbiology. 2021;59(2):e02589–20. 10.1128/JCM.02589-20 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Lanser L, Bellmann-Weiler R, Öttl K-W, Huber L, Griesmacher A, Theurl I, et al. Evaluating the clinical utility and sensitivity of SARS-CoV-2 antigen testing in relation to RT-PCR Ct values. Infection. 2020. 10.1007/s15010-020-01542-0 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Abbott. PanBio Covid-19 Ag Rapid Test Device Instruction for Use 2020 19.11.2020.
  • 14.Corman VM, Landt O, Kaiser M, Molenkamp R, Meijer A, Chu DK, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Euro Surveill. 2020;25(3). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)—a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377–81. 10.1016/j.jbi.2008.08.010 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Bangor A KP, Miller JT.. An Empirical Evaluation of the System Usability Scale. Intl Journal of Human–Computer Interaction. 2008;24:574–94. [Google Scholar]
  • 17.Altman DG, Bland JM. Diagnostic tests. 1: Sensitivity and specificity. BMJ. 1994;308(6943):1552. 10.1136/bmj.308.6943.1552 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 18.Cevik M, Tate M, Lloyd O, Maraolo AE, Schafers J, Ho A. SARS-CoV-2, SARS-CoV, and MERS-CoV viral load dynamics, duration of viral shedding, and infectiousness: a systematic review and meta-analysis. The Lancet Microbe. 2021;2(1):e13–e22. 10.1016/S2666-5247(20)30172-5 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Jefferson T, Spencer E., Brassey J., Heneghan C. Viral cultures for COVID-19 infectivity assessment. Systematic review. medRix 2020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Bulilete O, Lorente P, Leiva A, Carandell E, Oliver A, Rojo E, et al. Evaluation of the Panbio rapid antigen test for SARS-CoV-2 in primary health care centers and test sites. medRxiv. 2020:2020.11.13.20231316. [Google Scholar]
  • 21.Kissler SM, Fauver JR, Mack C, Tai C, Shiue KY, Kalinich CC, et al. Viral dynamics of SARS-CoV-2 infection and the predictive value of repeat testing. medRxiv. 2020:2020. [Google Scholar]
  • 22.Lindner AK, Nikolai O, Kausch F, Wintel M, Hommes F, Gertler M, et al. Head-to-head comparison of SARS-CoV-2 antigen-detecting rapid test with self-collected anterior nasal swab versus professional-collected nasopharyngeal swab. medRxiv. 2020:2020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Abdulrahman A, Mustafa F, AlAwadhi AI, Alansari Q, AlAlawi B, AlQahtani M. Comparison of SARS-COV-2 nasal antigen test to nasopharyngeal RT-PCR in mildly symptomatic patients. medRxiv. 2020:2020.11.10.20228973. [Google Scholar]
  • 24.Lee RA, Herigon JC, Benedetti A, Pollock NR, Denkinger CM. Performance of Saliva, Oropharyngeal Swabs, and Nasal Swabs for SARS-CoV-2 Molecular Detection: A Systematic Review and Meta-analysis. Journal of Clinical Microbiology. 2021:JCM.02881-20. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction–Based SARS-CoV-2 Tests by Time Since Exposure. Annals of Internal Medicine. 2020;173(4):262–7. 10.7326/M20-1495 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Sun J, Xiao J, Sun R, Tang X, Liang C, Lin H, et al. Prolonged Persistence of SARS-CoV-2 RNA in Body Fluids. Emerging Infectious Disease journal. 2020;26(8):1834. 10.3201/eid2608.201097 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Larremore DB, Wilder B, Lester E, Shehata S, Burke JM, Hay JA, et al. Test sensitivity is secondary to frequency and turnaround time for COVID-19 surveillance. medRxiv. 2020:2020.06.22.20136309. 10.1101/2020.06.22.20136309 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.van Beek J, Igloi Z, Boelsums T, Fanoy E, Gotz H, Molenkamp R, et al. From more testing to smart testing: data-guided SARS-CoV-2 testing choices. medRxiv. 2020:2020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Paltiel AD, Zheng A, Walensky RP. Assessment of SARS-CoV-2 Screening Strategies to Permit the Safe Reopening of College Campuses in the United States. JAMA Netw Open. 2020;3(7):e2016818. 10.1001/jamanetworkopen.2020.16818 [DOI] [PMC free article] [PubMed] [Google Scholar]

Decision Letter 0

Nicholas J Mantis

7 Jan 2021

PONE-D-20-40313

The Abbott PanBio WHO emergency use listed, rapid, antigen-detecting point-of-care diagnostic test for SARS-CoV-2

-

Evaluation of the accuracy and ease-of-use

PLOS ONE

Dear Dr. Denkinger,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Both Reviewers were very enthusiastic about the manuscript  and have provided lists of minor corrections/edits to be made. Please note that Reviewer 2's has several more substantive comments that should be addressed.

Please submit your revised manuscript by Feb 20 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Nicholas J Mantis

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please provide a sample size and power calculation in the Methods, or discuss the reasons for not performing one before study initiation.

3. We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.

In your revised cover letter, please address the following prompts:

a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. Please see http://www.bmj.com/content/340/bmj.c181.long for guidelines on how to de-identify and prepare clinical data for publication. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories.

We will update your Data Availability statement on your behalf to reflect the information you provide.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This is an excellent manuscript and I agree is an important contribution to the field about an important topic that should be accepted for publication after a minor revision.

I would change "CT" to "Ct" for cycle threshold as this is the convention

Line 39: would change "days of symptoms" to "day after symptom onset"

Line 44: change "days from symptom onset" to "days after symptom onset"

Line 51-52: sentence is awkward. Perhaps change to: "In March 2020, the World Health Organisation (WHO) emphasized the importance of access to testing..."

Line 53: would delete "all" from "remains the gold standard among all diagnostic tests"

Line 55: Would add a point about the limitations of PCR testing given the prolonged PCR positivity (not always a meaningful test in terms of telling whether someone has active replicating virus or transmission potential, see: https://wwwnc.cdc.gov/eid/article/26/8/20-1097_article

Line 64-65: sentence is awkward. Consider changing to "This manufacturer-independent study follows a WHO-approved..."

Line 69: would change "an excellent" to "a" to make more neutral

Line 72: I believe this is your first use of "POC" would add "point of care (POC)" since the first time it is being used

Line 87-88: This is not clear. Perhaps "Colloidal gold conjugated antibodies on the membrane strip react with viral antigens generating a colour change in the device window..."

Line 89: Awkward sentence. Perhaps change to "The results must be interpreting following 15 to 20 minutes of incubation..."

Line 98: change "in English or German" to "of English or German"

Line 98: change "a protocol" to "The study protocol"

Line 192: Would be helpful to know day of exposure relative to testing for all asymptomatic cases. If not known would write "14 participants without symptoms with recent high-risk contacts."

Line 203: would note that this sensitivity and specificity is for people with symptoms or a recent close confirmed contact with SARS-CoV-2 infection

Would add a new paragraph between your current first and second paragraphs in the discussion quickly reviewing viral load dynamics. Ie viral loads rise before symptom onset and peak around symptom onset and decline quickly after symptom onset. Should also note that the period of transmission for immunocompetent adults with symptomatic infection is from a couple days before symptom onset to around a week after symptom onset. Here are a couple reviews of the topic: https://wwwnc.cdc.gov/eid/article/26/8/20-1097_article, https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30172-5/fulltext

Line 206: change "overall viral load" to "mean viral load"

Line 208: would change to "low viral loads in Berlin, later in the course of infection."

Line 210: would delete "false-negative" and change to "discordant results"

Line 212: would change perhaps to "is likely to detect the vast majority of people with SARS-CoV-2 infections with transmission potential,..."

Line 213: Add a sentence reminding readers that since sensitivity is so good during first week of symptoms (which is the period of transmission) these tests have great utility as public health tools.

Line 214: change "asymptomatic participants" to "participants without symptoms at the time of testing"

Line 216: would add a sentence noting that you did not assess whether these individuals eventually develop symptoms and could have therefore been presymptomatic at the time of testing. Given their high viral loads they are presumed to have transmission potential so very important for them to get a positive result so they can isolate.

Line 224: change to "the use in symptomatic patients within the first week of illness"

Line 241: Would add that a limitation is that for asymptomatic cases the time of exposure to high risk cases was not recorded. Note that if tests are done to early they cannot exclude infection since viral load may not yet have had time to rise. The importance of this is that a negative test performed too early should not be used to support removing an individual from quarantine if a high risk exposure was very recent. Would cite: https://www.acpjournals.org/doi/10.7326/M20-1495

Reviewer #2: The authors evaluated the performance of the Panbio COVID-19 Ag Rapid Test Device for SARS-CoV-2 in nasopharyngeal swab specimens. For the ease of communication, Panbio stands for this kit in this review.

It was a prospective multicenter study, conducted in two sites in Germany, one was in Heidelberg while another was in Berlin. A total of 1108 individuals were recruited. Paired swabs were obtained for each individual, the ‘routine swab’ was used for RT-PCR while the ‘second study-exclusive swab’ was used for Panbio test.

Among these 1108 individuals, 106 were positive by RT-PCR. Among these 106 RT-PCR positive, 92 were Panbio positive, the sensitivity of the Panbio test was 86.8% (92/106).

There are two comments about this manuscript:

Comment 1

Lines 102-107

The description of the swabs used for RT-PCR and Panbio was confusing. There are four different terms of swabs: (1) routine swab, (2) nasopharyngeal swab, (3) combined nasopharyngeal and oropharyngeal swab, (4) study-exclusive swab.

Comment 2

There are at least five peer review articles evaluating the Panbio kit:

1. Linares et al. Panbio antigen rapid test is reliable to diagnose SARS-CoV-2 infection in the first 7 days after the onset of symptoms. J Clin Virol. 2020 Oct 16;133:104659. doi: 10.1016/j.jcv.2020.104659.

2. Fenollar et al. Evaluation of the Panbio Covid-19 rapid antigen detection test device for the screening of patients with Covid-19. J Clin Microbiol. 2020 Nov 2:JCM.02589-20. doi: 10.1128/JCM.02589-20.

3. Lanser et al. Evaluating the clinical utility and sensitivity of SARS-CoV-2 antigen testing in relation to RT-PCR Ct values. Infection. 2020 Nov 13. doi: 10.1007/s15010-020-01542-0.

4. Albert et al. Field evaluation of a rapid antigen test (Panbio™ COVID-19 Ag Rapid Test Device) for COVID-19 diagnosis in primary healthcare centers. Clin Microbiol Infect. 2020 Nov 12:S1198-743X(20)30697-2. doi: 10.1016/j.cmi.2020.11.004.

Based on these four articles, the sensitivity of the Panbio ranged from 60.8% to 79.6%.

5. Gremmels, H., et al., Real-life validation of the Panbio COVID-19 Antigen Rapid Test (Abbott) in community-dwelling subjects with symptoms of potential SARS-CoV-2 infection. EClinicalMedicine Available online 5 December 2020 https://doi.org/10.1016/j.eclinm.2020.100677

Table 2.

The authors reported high sensitivity of Panbio test 86.8% (92/106). It might be due to the high viral load study groups enrolled:

Figrue 2.

70 individuals (66.7%) with viral load >= 10^(7-8)

35 individuals (33.3%) with viral load <= 10^(6-7)

Lines 204-210

The authors also discussed the sensitivity difference observed between Berlin and Heidelberg.

The authors have to state the reasons for the high sensitivity of Panbio test clearly when comparing with those five studies (listed above), sensitivity ranged from 60.8%-81.1%.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2021 May 27;16(5):e0247918. doi: 10.1371/journal.pone.0247918.r002

Author response to Decision Letter 0


10 Feb 2021

Response to Reviewers

Journal Comments to the Author Response from Author

1. If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

Every participant signed a written consent form including a data protection section. Within this section it is clearly stated that the data will be pseudo anonymized for the data analysis. In addition, it is stated that the data will only be used for purposes of this study. The ethical committee of the University Heidelberg reviewed the study protocol and approved it on the 23.03.2020.

2. If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. Please see http://www.bmj.com/content/340/bmj.c181.long for guidelines on how to de-identify and prepare clinical data for publication. For a list of acceptable repositories, please see

http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories.

A data set, including the anonymized data will be uploaded to a data repository and the link will be shared.

Please provide a sample size and power calculation in the Methods, or discuss the reasons for not performing one before study initiation. The sample size calculations are included in the supplement.

Reviewer 1 Comments to the Author Response from Author

1. I would change "CT" to "Ct" for cycle threshold as this is the convention

Thanks, for this helpful comment, we have included the changes throughout the whole paper.

2. Line 39: would change "days of symptoms" to "day after symptom onset" and

Line 44: change "days from symptom onset" to "days after symptom onset"

Thank you for this comment, the changes have been included in the manuscript.

3. Line 51-52: sentence is awkward. Perhaps change to: "In March 2020, the World Health Organization (WHO) emphasized the importance of access to testing..."

Sentence has been changed and hopefully made more understandable, thank you for this remark.

4. Line 53: would delete "all" from "remains the gold standard among all diagnostic tests" We appreciate this suggestion and have included it in the manuscript.

5. Line 55: Would add a point about the limitations of PCR testing given the prolonged PCR positivity (not always a meaningful test in terms of telling whether someone has active replicating virus or transmission potential, see: https://wwwnc.cdc.gov/eid/article/26/8/20-1097_article We appreciate this comment and do understand that the RT-PCR method as a gold standard has its limitations. Yet, we would like to focus on the RT-PCR as the currently accepted gold standard as a comparison for the evaluation of PanBio. We have added text on the limitations of the PCR in the discussion

6. Line 64-65: sentence is awkward. Consider changing to "This manufacturer-independent study follows a WHO-approved..." We appreciate this suggestion and included it as recommended in the manuscript.

7. Line 69: would change "an excellent" to "a" to make more neutral We appreciate this recommendation and changed the wording to a more neutral way.

8. Line 72: I believe this is your first use of "POC" would add "point of care (POC)" since the first time it is being used We appreciate this suggestion and included it as recommended in the manuscript.

9. Line 87-88: This is not clear. Perhaps "Colloidal gold conjugated antibodies on the membrane strip react with viral antigens generating a colour change in the device window..." We appreciate this suggestion and included it as recommended in the manuscript.

10. Line 89: Awkward sentence. Perhaps change to "The results must be interpreting following 15 to 20 minutes of incubation..." Thank you. We appreciate this suggestion and included it as recommended in the manuscript.

11. Line 98: change "in English or German" to "of English or German" We appreciate this suggestion and included it as recommended in the manuscript.

12. Line 98: change "a protocol" to "The study protocol" We appreciate this suggestion and included it as recommended in the manuscript.

13. Line 192: Would be helpful to know day of exposure relative to testing for all asymptomatic cases. If not known would write "14 participants without symptoms with recent high-risk contacts." We do not have the exact data on day of exposure and therefore we appreciate this suggestion and changed the manuscript accordingly.

14. Line 203: would note that this sensitivity and specificity is for people with symptoms or a recent close confirmed contact with SARS-CoV-2 infection We appreciate this suggestion and included it as recommended in the manuscript.

15. Would add a new paragraph between your current first and second paragraphs in the discussion quickly reviewing viral load dynamics. Ie viral loads rise before symptom onset and peak around symptom onset and decline quickly after symptom onset. Should also note that the period of transmission for immunocompetent adults with symptomatic infection is from a couple days before symptom onset to around a week after symptom onset. Here are a couple reviews of the topic: https://wwwnc.cdc.gov/eid/article/26/8/20-1097_article, https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30172-5/fulltext Thank you for this recommendation. A short explanation has been added at line 259 to 261.

16. Line 206: change "overall viral load" to "mean viral load" We appreciate this suggestion and included it as recommended in the manuscript.

17. Line 208: would change to "low viral loads in Berlin, later in the course of infection." We appreciate this suggestion and included it as recommended in the manuscript.

18. Line 210: would delete "false-negative" and change to "discordant results" We appreciate this suggestion and have added discordant results to the sentences leaving false-negative in brackets for the clarification of these discordant results.

19. Line 212: would change perhaps to "is likely to detect the vast majority of people with SARS-CoV-2 infections with transmission potential,..." We appreciate this suggestion and included it as recommended in the manuscript.

20. Line 213: Add a sentence reminding readers that since sensitivity is so good during first week of symptoms (which is the period of transmission) these tests have great utility as public health tools. Thank you for this recommendation, a sentence has been added to the manuscript.

21. Line 214: change "asymptomatic participants" to "participants without symptoms at the time of testing" We appreciate this suggestion and included it as recommended in the manuscript.

22. Line 216: would add a sentence noting that you did not assess whether these individuals eventually develop symptoms and could have therefore been presymptomatic at the time of testing. Given their high viral loads they are presumed to have transmission potential so very important for them to get a positive result so they can isolate. Thank you for this recommendation, we have added a sentence to the manuscript explaining that data on later developed symptoms was not recorded during out study.

23. Line 224: change to "the use in symptomatic patients within the first week of illness" We appreciate this suggestion and included it as recommended in the manuscript.

24. Line 241: Would add that a limitation is that for asymptomatic cases the time of exposure to high-risk cases was not recorded. Note that if tests are done to early, they cannot exclude infection since viral load may not yet have had time to rise. The importance of this is that a negative test performed too early should not be used to support removing an individual from quarantine if a high-risk exposure was very recent. Would cite: https://www.acpjournals.org/doi/10.7326/M20-1495 Thank you for this recommendation, we have not recorded these data and have added this as a clear limitation to the study.

Reviewer 2 Comments to the Author Response from Author

1. Lines 102-107

The description of the swabs used for RT-PCR and Panbio was confusing. There are four different terms of swabs: (1) routine swab, (2) nasopharyngeal swab, (3) combined nasopharyngeal and oropharyngeal swab, (4) study-exclusive swab. We appreciate this comment, thank you very much. We have added words to clarify the explanation for the reader and hope this makes this paragraph less confusing.

2. There are at least five peer review articles evaluating the Panbio kit:

1. Linares et al. Panbio antigen rapid test is reliable to diagnose SARS-CoV-2 infection in the first 7 days after the onset of symptoms. J Clin Virol. 2020 Oct 16;133:104659. doi: 10.1016/j.jcv.2020.104659.

2. Fenollar et al. Evaluation of the Panbio Covid-19 rapid antigen detection test device for the screening of patients with Covid-19. J Clin Microbiol. 2020 Nov 2:JCM.02589-20. doi: 10.1128/JCM.02589-20.

3. Lanser et al. Evaluating the clinical utility and sensitivity of SARS-CoV-2 antigen testing in relation to RT-PCR Ct values. Infection. 2020 Nov 13. doi: 10.1007/s15010-020-01542-0.

4. Albert et al. Field evaluation of a rapid antigen test (Panbio™ COVID-19 Ag Rapid Test Device) for COVID-19 diagnosis in primary healthcare centers. Clin Microbiol Infect. 2020 Nov 12:S1198-743X(20)30697-2. doi: 10.1016/j.cmi.2020.11.004.

Based on these four articles, the sensitivity of the Panbio ranged from 60.8% to 79.6%.

5. Gremmels, H., et al., Real-life validation of the Panbio COVID-19 Antigen Rapid Test (Abbott) in community-dwelling subjects with symptoms of potential SARS-CoV-2 infection. EClinicalMedicine Available online 5 December 2020 https://doi.org/10.1016/j.eclinm.2020.100677 Thank you for this comment, we have reviewed the additionally mentioned publications and have included these in the manuscript, starting in the introduction and the discussion.

3. Table 2.

The authors reported high sensitivity of Panbio test 86.8% (92/106). It might be due to the high viral load study groups enrolled:

Figure 2.

70 individuals (66.7%) with viral load >= 10^(7-8)

35 individuals (33.3%) with viral load <= 10^(6-7) We appreciate this comment, thank you. In the discussion we have added a paragraph on viral load dynamics and pointed out that the test was very sensitive in the first week of symptoms, understood to be the week with the highest viral loads.

4. Lines 204-210

The authors also discussed the sensitivity difference observed between Berlin and Heidelberg.

The authors have to state the reasons for the high sensitivity of Panbio test clearly when comparing with those five studies (listed above), sensitivity ranged from 60.8%-81.1%. Thank you for this comment. We have included this information in the discussion and it can be observed that most studies support the high sensitivity within the first week of illness.

Attachment

Submitted filename: Rebuttal Letter_Response to Reviewers_PanBio.docx

Decision Letter 1

Nicholas J Mantis

17 Feb 2021

The Abbott PanBio WHO emergency use listed, rapid, antigen-detecting point-of-care diagnostic test for SARS-CoV-2

-

Evaluation of the accuracy and ease-of-use

PONE-D-20-40313R1

Dear Dr. Denkinger,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Nicholas J Mantis

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Acceptance letter

Nicholas J Mantis

3 May 2021

PONE-D-20-40313R1

The Abbott PanBio WHO emergency use listed, rapid, antigen-detecting point-of-care diagnostic test for SARS-CoV-2 - Evaluation of the accuracy and ease-of-use

Dear Dr. Denkinger:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Nicholas J Mantis

Academic Editor

PLOS ONE


Articles from PLoS ONE are provided here courtesy of PLOS

RESOURCES