Table 3. Sensitivity and specificity of different WHO presumptive diagnostic alternatives of HIV infection in children <18 months with a positive serological test for HIV in Rwanda.

Criteria	Sensitivity (CI)	Specificity (CI)	PPV	NPV
Interim WHO 2005	68.5 (59.6–76.6)	71.4 (62.1–79.6)	72.6	67.2
WHO 2006	76.6 (68.2–83.7)	52.7 (43–62.2)	64.1	67
Low CD4 cell count	55.6 (46.5–64.6)	78.5 (69.8–85.8)	74.1	61.4
WHO 2006 plus age >12 months	83.9 (76.2–89.9)	45.5 (36.1–55.2)	63	71.8
WHO 2006 plus CD4 cell count	88.7(81.8–93.8)	42.9 (33.5–52.6)	63.2	77.4

CI: confidence intervals.

PPV: positive predictive value.

NPV: negative predictive value.