TABLE 2.
Performance of urine and fingerprick whole blood cryptococcal antigen clinic-based testing compared to serum cryptococcal antigen laboratory-based testinga
| Sample | Sensitivity % (95% CI) | Specificity % (95% CI) | Positive predictive value % (95% CI) | Negative predictive value % (95% CI) |
|---|---|---|---|---|
| Urine | ||||
| All (n = 1311) | 63.8 (54.8–72.1) | 84.0 (81.7–86) | 29.9 (24.5–35.7) | 95.6 (94.1–96.7) |
| sCrAg titer <1:160 | 55.1 (44.1–65.6) | 84.0 (81.7–86) | 20.5 (15.6–26.2) | 96.1 (94.8–97.2) |
| sCrAg titer ≥1:160 | 84.2 (68.7–94) | 84.0 (81.7–86) | 14.4 (10.1–19.7) | 99.4 (98.7–99.8) |
| CD4 count <50 cells/μL | 65.3 (55–74.6) | 83.5 (80.8–86) | 32.3 (25.9–39.3) | 95.2 (93.4–96.7) |
| CNS disease | 91.7 (61.5–99.8) | 84.0 (81.7–86.0) | 5.5 (2.8–9.6) | 99.9 (99.4–100) |
| Fingerprick whole blood | ||||
| All (n = 1312) | 48.0 (39.1–57.1) | 99.5 (98.9–99.8) | 91 (81.5–96.6) | 94.7 (93.3–95.9) |
| sCrAg titer <1:160 | 33.7 (24–44.5) | 99.5 (98.9–99.8) | 83.3 (67.2–93.6) | 95.2 (93.9–96.4) |
| sCrAg titer ≥1:160 | 81.6 (65.7–92.3) | 99.5 (98.9–99.8) | 83.8 (68–93.8) | 99.4 (98.8–99.8) |
| CD4 count <50 cells/μL | 50.0 (39.7–60.3) | 99.6 (98.9–99.9) | 94.2 (84.1–98.8) | 94.3 (92.5–95.8) |
| CNS disease | 91.7 (61.5–99.8) | 99.5 (98.9–99.8) | 64.7 (38.3–85.8) | 99.9 (99.5–100) |
| Fingerprick whole blood + urine | ||||
| All (n = 1310) | 70.1 (61.2–77.7) | 83.8 (81.5–85.8) | 31.7 (26.3–37.5) | 96.3 (94.9–97.3) |
a
sCrAg, serum cryptococcal antigen; CNS, central nervous system; CI, confidence interval. Fingerprick and urine results were combined for each patient and positivity was considered by 1 of the 2 methods.