Table 1.

Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of ultrasensitive heat-denatured p24 antigen assay (Up24) results for viral load by reverse transcriptase-polymerase chain reaction (RT-PCR) in samples collected from participants prior to antiretroviral therapy (ART) and during ART (CI, confidence interval).

	Sensitivity n/N* (%, 95% CI)	Specificity n/N^ (%, 95% CI)	PPV n/N¶ (%, 95% CI)	NPV n/N§ (%, 95% CI)
Not on ART (N=213)	153/211 73 (66–79)	2/2 100	153/153 100	2/60 3 (0–8)
On ART (N=181)	40/69 58 (46–70)	74/112 66 (57–75)	40/78 51 (40–62)	74/103 72 (63–81)
All participants (N=394)	193/280 69 (64–74)	76/114 67 (62–72)	193/231 84 (80–88)	76/163 47 (42–52)

^*Number of samples positive by RT-PCR (>2.6 log₁₀ copies/ml) and Up24 (>1.9 log₁₀ fg/ml)/total positive by RT-PCR (>2.6 log₁₀ copies/ml).

^{^}Number of samples negative by RT-PCR (≤2.6 log₁₀ copies/ml) and Up24 (≤1.9 log₁₀ fg/ml)/total negative by RT-PCR (≤2.6 log₁₀ copies/ml).

^¶Number of samples positive by RT-PCR (>2.6 log₁₀ copies/ml) and Up24 (>1.9 log₁₀ fg/ml)/total positive by Up24 (>1.9 log₁₀ fg/ml).

^§Number of samples negative by RT-PCR (≤2.6 log₁₀ copies/ml) and Up24 (≤1.9 log₁₀ fg/ml)/total negative by Up24 (≤1.9 log₁₀ fg/ml).