Table 2.
Characteristics of the population on the eligible studies included.
| Author | Country | Population |
Symptoms | Diagnosis | RNA extraction kit | PCR-Kit | Target gene for RT-PCR test Swab type |
Swab type |
Saliva collection | |
|---|---|---|---|---|---|---|---|---|---|---|
| N | Age | |||||||||
|
Abdollahiet et al. |
Iran | 80 (emergency unit’s triage) |
56.5 ± 16.8 [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], [91], [92] |
Symptomatic patients | Viral RNA detection with PCR from ONS | Viral Nucleic Acid Extraction kit by RBC Bioscience | 2019-nCOV RT-PCR-Fluorescent Probing of Sansure Biotech (Changsha, China) | NR | Oro-Nasopharyngeal | Whole saliva (spit) |
|
Babadyet et al. |
United States of America | 87 (employees of hospital) |
NR | Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | NUCLISENS EasyMag or Chemagic 360 | ABI 7500 Fast or the QuantStudio 5 | The N1 and N2 genes | Nasopharyngeal | Whole saliva (spit) |
|
Balaskaet et al. |
Greece | 420 (diagnosing patients and screening healthcare workers) |
44.7 ± 13 | Symptomatic and asymptomatic | Viral RNA detection with PCR from NPS | NR | Advanta™ Dx SARS-CoV-2 RT-PCR Assay (Fluidigm Corporation, San Francisco, USA) and NeumoDxTM SARS-CoV-2 Assay |
The N1, N2, and RP primers and probes (Advanta), and Nsp2 and N genes (Neumo) |
Nasopharyngeal | Whole saliva (spit) |
|
Baratet et al. |
United States of America | 459 (drive-through testing center and hospital) |
42 [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85], [86], [87], [88] |
Symptomatic patients | Viral RNA detection with PCR from NPS | NucliSENS easyMAG platform (bioMérieux, France) |
ABI 7500 fast real-time PCR system (Thermo Fisher Scientific, Waltham, MA) |
The N1, N2, and RNase P primers and probes | Nasopharyngeal | Whole saliva (drooling method) |
|
Bergevinet et al. |
Canada | 773 (hospital patients) |
44 [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58] |
Symptomatic and asymptomatic | Viral RNA detection with PCR from ONS | Seegene Starlet (Seegene) | Allplex 2019-nCoV Assay (Seegene) |
The E, RdRp and N genes | Oro-Nasopharyngeal | Whole saliva (drooling method) |
| Bhattacharya et al. | India | 74 (hospitalized patients) |
NR | Mild to‐ moderate symptoms |
Viral RNA detection with PCR from NPS | QIAamp Viral RNA Mini Kit | ABI 3500xL Dx Genetic Analyzer | The ORF1 and E genes | Nasopharyngeal | Whole saliva |
|
Borghiet et al. |
Italy | 192 (hospital) |
NR | Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | Direct qPCR | Applied Biosystem 7500 Fast instrument | The N1 and RP genes | Nasopharyngeal | Whole saliva |
|
Callahanet et al. |
United States of America | 385 (drive-through collection sites) |
NR | Symptomatic and asymptomatic | Viral RNA detection with PCR from NPS | NR | Abbott m2000 and Abbott Alinity RealTime SARS-CoV-2 assay | NR | Nasopharyngeal | Whole saliva (spit/drool) |
|
Carrilloet et al. |
Philippines | 197 (health care workers and outpatient of hospital) |
32 [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64] |
Symptomatic patients | Viral RNA detection with PCR from NPS | GenAmplify™ Viral RNA Purification Kit (The Manila HealthTek, Inc.) |
2019-nCoV Nucleic Acid Diagnostic Kit (Sansure Biotech Inc.) or Real-Time Fluorescent RT-PCR Kit for Detecting SARS-CoV-2 (BGI Genomics Co. Ltd.) |
NR | Nasopharyngeal | Whole saliva (snort-spit) |
|
Carrouelet et al. |
France | 31 (ambulatory patients) |
43.0 ± 15.5 [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75] |
Symptomatic and asymptomatic | Viral RNA detection with PCR from NPS | NucliSens easyMAG instrument (bioMérieux, France) | Invitrogen SuperscriptTM III Platinum One-Step qRT-PCR system (Invitrogen, France) |
The RdRp-IP2 and RdRp- IP4 |
Nasopharyngeal | Whole saliva (spit) |
|
Caulleyet et al. |
Canada | 272 (testing center) |
NR | Asymptomatic, high-risk and mild symptoms |
NR | NR | RT-PCR (NR) | The E gene | Nasopharyngeal | Whole saliva (spit) |
|
de Oliveiraet et al. |
Brazil | 400 (testing center) |
> 18 | Symptomatic | Viral RNA detection with PCR from ONS | Chemagic™ 360 instrument (PerkinElmer, USA) |
QuantStudio 5™ instrument (ThermoFisher Scientific, USA) and TaqPath™ Covid-19 CE-IVD RT-PCR kit (ThermoFisher Scientific, USA) |
The N and RNAseP targets | Oro-Nasopharyngeal | Whole saliva (spit) |
|
Doganet et al. |
Turkey | 98 (hospitalized patients) |
NR | Moderate-severe disease | Viral RNA detection with PCR from NPS and COVID-19 symptoms |
Direct Detection Kit (Coyote Bioscience Co., Ltd) | Biorad CFX 96 Real-Time PCR systems |
The Orflab and N genes | Nasopharyngeal | Whole saliva (drooling method) |
|
Echavarriaet et al. |
Argentina | 174 (hospital-emergency) |
31 [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50] |
Symptomatic | Viral RNA detection with PCR from NPS | Quick‐RNA™ Viral Kit, Zymo Research Corp | CFX 96 Deep Well™ Real Time System (BioRad) | The E gene | Nasopharyngeal | Whole saliva |
|
Genelhoudet et al. |
Brazil | 229 | NR | Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | NR | NR | NR | Nasopharyngeal | Whole saliva |
|
Getachewet et al. |
Ethiopia | 280 | NR | Symptomatic patients |
Viral RNA detection with PCR from NPS | RNA Extraction and Purification reagent, by DAAN Gene Co. LTD | RT-PCR Kit fir 2019 n-CoV, by BGI Biotechnology | ORF1ab | Nasopharyngeal | Whole saliva |
|
Ghaniet et al. |
Pakistan | 48 (patients) |
35.9 ± 1.3 | NR | Viral RNA detection with PCR from NPS | NR | NR | NR | Nasopharyngeal | Whole saliva (drooling method) |
|
Gonçalveset et al. |
Brazil | 194 | 39 ± 13 | Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | Maxwell 16 Viral Total Nucleic Acid Purification Kit, by Promega | 2019-nCov CDC qPCR Probe Assay, by Integrated DNA Technologies | N1, N2 and RNaseP genes | Nasopharyngeal | Whole saliva (spit) |
|
Güçlüet et al. |
Turkey | 64 (hospitalized and emergency department) |
51.04 ± 17.9 | Mild, moderate and advanced symptoms | Viral RNA detection with PCR from ONS and COVID-19 symptoms | EZ1 (Qiagen, Germany) device | RT-PCR SARS-CoV-2 (Primer Design, UK) kit. |
NR | Oro-Nasopharyngeal | Whole saliva (drooling method) |
|
Guimarãeset et al. |
Brazil | 189 | 39.6 ± 12.3 | Symptomatic patients |
Viral RNA detection with PCR from NPS | Bio-Gene DNA/RNA Viral Extraction, by Bioclin | SARS-CoV-2 molecular kit, by Bio-Manguinhos | SARS-CoV-2 envelope gene | Nasopharyngeal | Whole saliva (spit) |
|
Hansonet et al. |
United States of America | 353 (drive-through test center) |
35 [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75] |
NR | NR | NA | Hologic Aptima SARS-CoV-2 transcription-mediated amplification (TMA) assay (Hologic Inc.) |
NA | Nasopharyngeal | Whole saliva (drooling method) |
|
Iwasakiet et al. |
Japan | 76 (suspicious and diagnosis) |
69 [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], [91], [92], [93], [94], [95], [96], [97] |
Mild to moderate disease | NR | QIAamp Viral RNA Mini Kit | One-Step Real-Time RT-PCR Master Mixes and tepOnePlus Real Time PCR System |
NR | Nasopharyngeal | Whole saliva (spit) |
|
Jamalet et al. |
Canada | 91 (inpatients at hospital) |
66 [23–106] |
NR | NR | NR | Allplex 2019-nCoV Assay (100 T) | The RdRp, E and N genes | Nasopharyngeal | Whole saliva (spit) |
|
Jenkinset et al. |
United Kingdom | 413 | NR | Asymptomatic and symptomatic patients | Viral RNA detection with RT-qPCR from ONS | NR | A triplexed combination of DNA primer and probe oligonucleotides (from the CDC and FDA approved) | The N and e genes | Oro-Nasopharyngeal | Whole saliva (drooling method) |
|
Joet et al. |
South Korea | 338 | 39 | Asymptomatic and symptomatic patients | Viral RNA detection with RT-PCR from NPS | Real-Prep Viral DNA/RNA kit, by BioSeWoon | Real-Q Direct SARS-CoV-2 Detection Kit, by BioSeWoon | E and RdRp genes | Nasopharyngeal | Whole saliva (drooling method) |
|
Kandelet et al. |
Canada | 429 (hospital) |
42 [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54] |
Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | Promega Maxwell HT Viral TNA Kit (NPS) | CFX96 Touch Real-time PCR detection system (NPS) Roche cobas® 6800 analyzer and Roche cobas® SARS-CoV-2 assay (saliva) |
The E gene and 5′-UTR (NPS) The E and ORF1 genes (saliva) |
Nasopharyngeal | Whole saliva (drooling method) |
|
Landryet et al. |
United States of America | 124 (Hospital drive through testing) |
NR | Symptomatic outpatients suspected | NR | EasyMag | RT-PCR (NR) | The N1, N2 and RNAse P genes |
Nasopharyngeal | Whole saliva (spit) |
|
Marxet et al. |
United States of America | 497 | NR | Asymptomatic and symptomatic patients | Viral RNA detection with RT-PCR from NPS | NR | NR | N1 and N2 genes | Nasopharyngeal | Whole saliva (spit) |
|
Maticet et al. |
Canada | 74 (Inpatients, residents of long-term care facilities, healthcare workers, and outpatients) |
51 [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], [91], [92], [93], [94], [95] |
Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | MagNA Pure 96 System | LightMix® ModularDx SARS-CoV (COVID19) E-gene assay and LightCycler® Multiplex RNA Virus Master |
The E gene | Nasopharyngeal | Whole saliva (spit) |
|
Mestdaghet et al. |
Belgium | 2469 | 31–40 | Asymptomatic and symptomatic patients | Viral RNA detection with RT-qPCR from NPS | Total RNA Purification Kit, by Norgen Biotech; and Magnetic bead-based RNA extraction, by University of Liége | iTaq one-step RT-qPCR mastermix, by BioRad; and TaqPath COVID-19 RT-qPCR Combo Kit, by Thermo Fisher | ORF1ab, N, S and MS2 genes | Nasopharyngeal | Whole saliva (spit) |
| McCormick-Baw et al. | United States of America | 155 (hospital) |
47.8 | Symptomatic patients | Viral RNA detection with PCR from NPS | Direct | Cepheid Xpert Xpress SARS-CoV-2 RT-PCR | The E and N2 genes | Nasopharyngeal | Whole saliva (drooling method) |
|
Miguereset et al. |
France | 123 (hospitalized and ambulatory patients) |
43 (NR) |
Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | NR | RT-PCR Panther Fusion™ module | NR | Nasopharyngeal | Whole saliva (spit) |
|
Moreno-Contreraset et al. |
Mexico | 71 (ambulatory patients) |
41 ± 14.4 | Symptomatic patients | Viral RNA detection with PCR from ONS | QIAamp viral RNA minikit | StarQ one-step RT-PCR | The gene E and RNase P | Oro-Nasopharyngeal | Whole saliva (spit) |
|
Pasomsubet et al. |
Thailand | 200 (hospital) |
36 [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48] |
Symptomatic patients | Viral RNA detection with PCR from ONS | MagDEA® Dx reagents (automated nucleic acid extraction) | CFX96 Real-Time Detection System | The ORF1ab and N gene | Oro-Nasopharyngeal | Whole saliva |
|
Potteret et al. |
United States of America | 311 (Barnes-Jewish Hospital ED) |
NR | Symptomatic patients | Viral RNA detection with PCR from NPS saliva |
NUCLISENS-easyMAG | Lyra, SARS-CoV-2 assay, COVID-19 Test (Biofire), cobas 6800 SARS-CoV-2 Test (Roche), or the Xpert Xpress SARS-CoV-2 (Cepheid) | NR | Nasopharyngeal | Whole saliva |
| Rodriguez-Florez et al. | Mexico | 30 (clinical sample) |
NR | Symptomatic patients | Viral RNA detection with PCR | QIAamp Viral RNA Mini, Qiagen, MD, United States) or SalivaDirect nucleic acids extraction protocol |
SARS-CoV-2 Real-Time PCR kit (Vircell, Granada, Spain). |
E gene | Nasopharyngeal | Whole saliva |
|
Sahajpalet et al. |
United States of America | 240 (healthcare or a community setting) |
NR | NR | Viral RNA detection with PCR | Protocol U, Protocol or Saliva All |
NR | N gene and ORF1ab |
Nasopharyngeal | Whole saliva |
|
Senoket et al. |
United Arab Emirates | 401 (hospital) |
35.5 ± 9.5 | Asymptomatic and symptomatic patients | Viral RNA detection with PCR from NPS | Chemagic viral RNA extraction kit on the automated Chemagic™ 360 Nucleic Acid Extractor | NeoPlex COVID-19 kit | The RdRp and N gene targets | Nasopharyngeal | Whole saliva (spit) |
|
Sogbesanet et al. |
United States of America | 89 (Individuals) |
20–83 | Symptomatic patients |
Viral RNA detection with PCR | NR | Cobas SARS-CoV-2 test | ORF1ab and E gen | Nasopharyngeal | Whole saliva |
|
Uddinet et al. |
Bangladesh | 596 (Workers hospital) |
28–47 | Symptomatic patients |
Viral RNA detection with PCR | QIAamp viral RNA mini kit (quigen, Germany) | iTaq universal probes one-step RT-qPCR kit | RdRp and N genes | Nasopharyngeal | Whole saliva |
|
Uwaminoet et al. |
Japan | 196 (hospitalized patients and university staff) |
NR | Symptomatic patients | Viral RNA detection with PCR from NPS | NR | 2019 Novel Coronavirus Detection Kit (Shimadzu, Kyoto, Japan) |
The N1 and N2 primers and probes | Nasopharyngeal | Whole saliva |
|
Vazet et al. |
Brazil | 155 (healthcare workers and patients at the COVID-19 ward) |
40 (33–48.5) |
Symptomatic patients – mild to moderate symptoms | Viral RNA detection with PCR from ONS | QIAGEN QIAamp® RNA Mini Kit |
RT-PCR - (NR - ONS) and Applied Biosystems 7500 Real Time PCR detector (saliva) |
The E and RdRp genes | Oro-Nasopharyngeal | Whole saliva (spit) |
|
Yokotaet et al. |
Japan | 1924 (contact tracing) |
45 [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66] |
Asymptomatic patients | Viral RNA detection with PCR from NPS | QIAsymphony DSP Virus/Pathogen kit and QIAamp Viral RNA Mini Kit | One step qRT-PCR was performed using THUNDERBIRD® Probe One-step qRT-PCR Kit and 7500 Real-time PCR Systems | The N2 primers | Nasopharyngeal | Whole saliva |
|
Yokotaet et al. |
Japan | 42 (Patients) |
27–93 | Symptomatic patients |
Viral RNA detection with PCR | QIAsymphony DSP Virus/Pathogen kit and QIAamp Viral RNA Mini Kit (QIAGEN, Hilden, Germany) |
Thunderbird Probe One-step qRT-PCR Kit |
N gene | Nasopharyngeal | Whole saliva |
Note: NR: Not reported; ONS: Oro-Nasopharyngeal Swab, NPS: Nasopharyngeal Swab.