Rubio‐Garrido 2019.

Study characteristics
Patient Sampling	Samples collected in the Democratic Republic of the Congo (DRC) tested in Spain. HIV+ DBS samples tested by viral load assays. From April to November 2016, 160 DBS were collected at Monkole Hospital (Kinshasa, DRC) from 85 children (60 HIV‐non‐infected, 18 HIV‐positive, 7 HIV‐exposed) and 75 HIV‐infected adults (65 treated with clinical suspicion of treatment failure, 10 naive).
Patient characteristics and setting	84 (14 children and 70 adults) on ART (n = 69), ART naive (n = 10), ART unknown (n = 5); samples collected from the Democratic Republic of the Congo and tested in a laboratory in Spain.
Index tests	Xpert HIV‐1 Viral Load (Cepheid) on frozen whole blood DBS samples tested in a lab in Spain. Assays based on real‐time PCR, providing an assay‐specific cycle threshold (Ct), which inversely correlates with the starting concentration of the viral genome in the infected specimen. Ct values were recorded following DBS VL quantification by both Xpert VL and Roche VL platforms using 1 DBS dot in each sample.
Target condition and reference standard(s)	High HIV viral load > 1000 copies/mL and > 40 copies/mL; Roche COBAS AmpliPrep/COBAS TaqMan HIV‐1 Test v2.0.
Flow and timing	From April to November 2016, 160 DBS were collected at Monkole Hospital (Kinshasa, Democratic Republic of Congo). They were dried separately on a drying‐rack overnight at room temperature in Monkole Hospital, sealed in a zip‐lock plastic bag with desiccant bags, and stored at −20 °C until transported in dry ice to the laboratories in Madrid and Pamplona, Spain, where children and adult samples, respectively, were stored at −80 °C until further use. HIV diagnosis was firstly performed in DRC using rapid serological tests; in Navarra, Spain, HIV serostatus was confirmed in all adults by two 4th‐generation immunoassays: Elecsys HIV combi PT (Roche) and VIDAS HIV Duo Quick (bioMérieux). HIV‐1 viraemia was quantified using Cepheid Xpert HIV‐1 Viral Load (Xpert VL) 35 and COBAS AmpliPrep/COBAS TaqMan HIV‐1 Test v2.0 (Roche VL) 36 in all HIV+ DBS, both techniques based on real‐time amplification of HIV genome.
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?	Unclear
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Unclear
Could the patient flow have introduced bias?		Unclear risk