TABLE 1

Sensitivities and specificities for detection of virological failurea in DBS and plasma

VL assay and labPlasma-DBS pairs (n = 382)No. (%) of pairs with plasma VL of ≥1,000 copies/ml (n = 155)No. of false negatives/total no. of pairs with plasma VL of ≥1,000 copies/mlbNo. of false positives/total no. of pairs with plasma VL of <1,000 copies/mlcSensitivity (% [95% CI])dSpecificity (% [95% CI])No. of plasma-DBS pairs with detectable VLVL difference of <0.5 log10 copies/ml (%)
m2000rt assay173
    Lab B6024 (40)0/241/36100 (85.8–100)97.2 (85.5–99.9)2624 (92)
    Lab C5313 (25)0/137/40100 (75.3–100)82.5 (67.2–92.7)1812 (67)
    Lab D6012 (20)3/121/4875.0 (42.8–94.5)97.9 (88.9–99.9)108 (80)
Generic G2 assay118
    Lab A6016 (27)1/1617/4493.8 (69.8–99.8)61.4 (45.5–75.6)2316 (70)
    Lab F5823 (40)2/2314/3591.3 (72.0–98.9)60.0 (42.1–76.1)3718 (49)
NucliSENS assay91
    Lab E9167 (74)10/671/2485.1 (74.3–92.6)95.8 (78.9–99.9)7628 (37)
  • a Virological failure is defined as a VL of ≥1,000 copies/ml.

  • b False negatives are samples with a VL of ≥1,000 copies/ml in plasma but a VL of <1,000 copies/ml in DBS.

  • c False positives are samples with a VL of <1,000 copies/ml in plasma but a VL of ≥1,000 copies/ml in DBS.

  • d CI, confidence interval.