Feasibility and Field Performance of a Simultaneous Syphilis and HIV Point-of-Care Test Based Screening Strategy in at Risk Populations in Edmonton, Canada

Table 3

Performance characteristics of syphilis and HIV point-of-care testing.

Factor	Positive (%)	Negative (%)	Total (%)	Performance^a (%; 95% CI)
Syphilis^b
POCT result	29 (2.8)	990^c (97.2)	1019 (100.0)
Standard test Result	34 (3.3)	985 (96.7)	1019 (100.0)
Sensitivity				85.3 (68.9–95.0)
Specificity				100.0 (99.6–100^d)
PPV				100.0 (88.1–100^d)
NPV				99.5 (98.8–99.8)
HIV^e
POCT result	6 (0.6)	993^f (99.4)	999 (100.0)
Standard test Result	4 (0.5)	995 (99.6)	999 (100.0)
Sensitivity				100.0 (39.8–100^d)
Specificity				99.8 (99.3–100)
PPV				66.7 (22.3–95.7)
NPV				100.0 (99.6–100^d)

CI: confidence interval; POCT: point-of-care test; PPV: positive predictive value; NPV: negative predictive value.
^aStandard testing was used as gold standard.
^bCalculations do not include 1 invalid POCT result (negative on follow-up standard testing).
^cDoes not include 4 negative specimens which did not have standard follow-up testing performed (insufficient quantity (𝑛=2), specimen not labelled (𝑛=1), unable to draw blood (𝑛=1)).
^dOne-sided, 97.5% confidence interval.
^eCalculations do not include 3 invalid POCT results (negative on follow-up standard testing).
^fDoes not include 9 negative which were indeterminate (𝑛=3) or did not have standard testing performed (insufficient quantity (𝑛=4), or missing specimen (𝑛=2)).