1. Sources of variation in accuracy estimates.
| Sensitivity (%) | Specificity (%) | Comparisons | ||
| Main meta‐analysisa | @ ≥ 1000 copies/mL n = 20 | 96.6 (94.8 to 97.8) | 95.7 (90.8 to 98.0) | ‐ |
| Subgroup analysisa | ||||
| Test type | Xpert HIV‐1 Viral Load test (n = 8) | 96.9 (94.0 to 98.4) | 95.6 (89.4 to 98.2) | Difference in sensitivity Xpert versus Sambab 2.1% (−1.2 to 5.3) |
| SAMBA HIV‐1 Semi‐Q Test (n = 9) | 94.8 (91.6 to 96.9) | 97.2 (95.3 to 98.4) | Difference in specificity Xpert versus Sambab −1.7% (−5.9 to 2.5) |
|
| Location | Central lab (n = 10) | 96.5 (93.7 to 98.1) | 95.8 (84.0 to 99.0) | Difference in sensitivity Lab versus near patientb,c −0.1% (−3.0 to 2.7) |
| Near patientc (n = 10) | 96.7 (94.1 to 98.2) | 95.6 (90.8 to 98.0) | Difference in specificity Lab versus near patientb,c 0.2% (−6.5 to 6.9) |
|
| Sensitivity analysisa | ||||
| ART status | All on ART (n = 9) | 96.5 (92.6 to 98.4) | 90.1 (71.6 to 97.0) | ‐ |
| Region | Africa (n = 16) | 95.3 (94.4 to 96.1) | 92.1 (91.4 to 92.8) | ‐ |
| Age | Adults only (n = 13) | 97.2 (95.6 to 98.2) | 97.4 (94.3 to 98.8) | ‐ |
| Test group | Commercial assay (n = 18) | 96.1 (94.2 to 97.4) | 96.9 (95.2 to 98.1) | ‐ |
| Sample type | Plasma (n = 17) | 96.0 (94.0 to 97.3) | 97.0 (96.1 to 97.8) | ‐ |
| Threshold | Threshold @ ≥ 40 copies/mL (n = 7) | 85.6 (74.9 to 92.2) | 95.9 (90.7 to 98.2) | ‐ |
Abbreviations: ART: antiretroviral therapy
aWe fitted simplified univariable models for sensitivity and specificity separately, using a random‐effects model when the bivariate models did not converge to give a model estimate. bIndirect test comparisons were conducted. c'Near the patient' implies that testing was done onsite in the health facility laboratory or decentralized peripheral laboratory.