TABLE 2.
Diagnostic accuracy of Visitect CD4 at a cutoff of ≤200 cells/mm3 from GLMMa
| Factor | Value (95% CI) |
Inferenceb and heterogeneity |
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model A |
Model B |
Model C |
|||||||||||||
| Sens | Spec | PPV | NPV | Sens | Spec | PPV | NPV | Sens | Spec | PPV | NPV | LR (χ2) | P | ICC | |
| Overall | 87.9 (76.3–99.5) | 75.5 (69.9–81.2) | 30.0 (17.9–42.1) | 98.4 (97.2–99.7) | 0.68 | ||||||||||
| Operator | χ2(4) = 6.65 | 0.156 | 0.69 | ||||||||||||
| Lab tech | 85.4 (69.0–100) | 74.4 (66.8–82.1) | 31.1 (17.5–44.7) | 97.8 (94.8–100) | |||||||||||
| Nurse | 88.0 (74.8–100) | 79.1 (73.1–85.1) | 35.1 (20.9–49.3) | 98.4 (96.6–100) | |||||||||||
| Counselor | 90.4 (75.4–100) | 70.3 (62.3–78.3) | 27.5 (15.1–39.7) | 98.9 (96.7–100) | |||||||||||
| Sample type | χ2(2) = 12.31 | 0.002 | 0.70 | ||||||||||||
| Venous | 91.1 (80.4–100) | 73.1 (66.9–79.3) | 28.9 (16.9–40.8) | 98.9 (97.3–100) | |||||||||||
| Finger prick | 80.2 (62.0–98.3) | 83.4 (76.8–90.1) | 34.2 (19.1–49.3) | 97.1 (93.9–100) | |||||||||||
GLMM generalized through use of a logit link function and binomial distribution with a random intercept for test participant (n = 147). PPV and NPV estimates were determined from ordinary logit GLM with cluster robust standard errors. GLMM analyses would not converge reliably. Sens, test sensitivity; Spec, test specificity; PPV, positive predictive value; NPV, negative predictive value; ICC, intraclass correlation coefficient from random intercept GLMM; model A, unadjusted; model B, operator by test interaction and main effect (not shown); model C = Blood sample type by test interaction and main effect (not shown).
Likelihood ratio (LR) tests comparing nested less-constrained models (B and C) with model A.