| Study characteristics |
| Patient Sampling |
A total of 42 Xpert HIV‐1 VL assays were performed on plasma samples on whole blood samples collected consecutively from known HIV‐positive South African women who attended for routine study visits in the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 002 study. |
| Patient characteristics and setting |
HIV‐positive adult women (55% on ART); South Africa. |
| Index tests |
Xpert HIV‐1 Viral Load were performed in the clinic on fresh (31) plasma samples and frozen (11) plasma samples (field/clinic validation study). |
| Target condition and reference standard(s) |
High HIV viral load > 1000 copies/mL; Roche TaqMan version 2 assay (Roche Diagnostics, Risch‐Rotkreuz, Switzerland). |
| Flow and timing |
Samples were collected in 5‐millilitre EDTA tubes. For the Xpert HIV‐1 VL assay, specimens were first centrifuged at 1200 revolutions per minute (rpm) for 10 minutes before transfer of 1 mL of plasma into the assay’s cartridge chamber using a sterile pipette. Assay was then loaded into the GeneXpert System for analysis. HIV viral load testing was performed with the Roche TaqMan version 2 assay (Roche Diagnostics, Risch‐Rotkreuz, Switzerland) as the gold‐standard diagnostic test. |
| 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? |
Yes |
|
|
| 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? |
Yes |
|
|
| If a threshold was used, was it pre‐specified? |
Yes |
|
|
| Could the conduct or interpretation of the index test have introduced bias? |
|
Low risk |
|
| Are there concerns that the index test, its conduct, or interpretation differ from the review question? |
|
|
Low concern |
| 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? |
Unclear |
|
|
| Did all patients receive the same reference standard? |
Unclear |
|
|
| Were all patients included in the analysis? |
Unclear |
|
|
| Could the patient flow have introduced bias? |
|
Unclear risk |
|
