Table 4. Cross tabulation of frequencies of negative and positive results for Schistosoma PCR in cervico-vaginal lavage compared to a pseudo-gold standard, with empirical sensitivities, specificities, positive and negative predictive values and 95% confidence intervals (CIs).

	Schistosoma PCR in CVL b
Pseudo gold standard a	Negative	Positive	Total
Negative	66	5	71
Positive	189	31	220
Total	255	36	291
Sensitivity (95% CI): 14.1 (9.8 to 19.4) Specificity (95% CI): 93.0 (84.3 to 97.7)

Missing data was not included in this analysis. CI: Confidence Interval

a. Sandy patches identified using clinical photocolposcopic examination or by computerised colourimetric image analysis [17, 26]

b. In-house Schistosoma polymerase chain reaction (PCR) [22].