| Study characteristics |
| Patient Sampling |
Study included samples collected between 2013 and 2014 from patients (confirmed HIV‐1 carriers) attending the AIDS clinic of the Sheba Medical Center. Plasma from whole blood samples collected in EDTA‐containing tubes was separated by centrifugation (1100 g for 5 min). Plasma samples (n = 404) spanning the full range of HIV‐1 viral loads were selected based on the NUCLISENS v2.0 results. |
| Patient characteristics and setting |
Samples from HIV‐1 positive patients (some on ART, others not); Sheba clinic in Israel |
| Index tests |
The Xpert HIV‐1 Viral Load assay on the GeneXpert platform (Cepheid Inc); frozen plasma samples in a laboratory |
| Target condition and reference standard(s) |
High HIV viral load results > 40 copies/mL, Abbott RealTime HIV‐1 assay |
| Flow and timing |
Plasma from whole blood samples collected in EDTA‐containing tubes was separated by centrifugation (1100 g for 5 min). An aliquot (0.5 mL) was initially tested with the NUCLISENS v2.0 assay as part of the regular monitoring of HIV‐1 copy numbers. Separate aliquots of the plasma samples were stored frozen at 20 °C in volumes required for the different assays, with a single freeze‐thaw cycle prior to analysis on the different platforms. On the day of analysis, the aliquots were thawed. |
| Comparative |
|
| Notes |
|
| Methodological quality |
| Item |
Authors' judgement |
Risk of bias |
Applicability concerns |
| DOMAIN 1: Patient Selection |
| Was a consecutive or random sample of patients enrolled? |
Unclear |
|
|
| Was a case‐control design avoided? |
Yes |
|
|
| Did the study avoid inappropriate exclusions? |
Unclear |
|
|
| Could the selection of patients have introduced bias? |
|
Unclear risk |
|
| Are there concerns that the included patients and setting do not match the review question? |
|
|
High |
| DOMAIN 2: Index Test (All tests) |
| Were the index test results interpreted without knowledge of the results of the reference standard? |
Unclear |
|
|
| If a threshold was used, was it pre‐specified? |
Yes |
|
|
| Could the conduct or interpretation of the index test have introduced bias? |
|
Unclear risk |
|
| Are there concerns that the index test, its conduct, or interpretation differ from the review question? |
|
|
High |
| DOMAIN 3: Reference Standard |
| Is the reference standards likely to correctly classify the target condition? |
Yes |
|
|
| Were the reference standard results interpreted without knowledge of the results of the index tests? |
Unclear |
|
|
| Could the reference standard, its conduct, or its interpretation have introduced bias? |
|
Unclear risk |
|
| Are there concerns that the target condition as defined by the reference standard does not match the question? |
|
|
Low concern |
| DOMAIN 4: Flow and Timing |
| Was there an appropriate interval between index test and reference standard? |
Yes |
|
|
| Did all patients receive the same reference standard? |
Yes |
|
|
| Were all patients included in the analysis? |
No |
|
|
| Could the patient flow have introduced bias? |
|
Low risk |
|
