Table 3.
Performance of the POC-CCA assay using different diagnostic tests as reference
| POC-CCA† | Reference test | Sensitivity, % (95% CI) | Specificity, % (95% CI) | PPV, % (95% CI) | NPV, % (95% CI) | Accuracy, % (95% CI) | Kappa index (95% CI) | |
|---|---|---|---|---|---|---|---|---|
| + | − | |||||||
| KK | ||||||||
| + | 32 | 19 | 29.6 (21.2–39.2) | 93.8 (90.4–96.2) | 62.8 (48.1–75.9) | 79.0 (74.4–83.0) | 77.0 (72.6–81.0) | 0.282 (0.179–0.385) |
| − | 76 | 285 | ||||||
| F_ddPCR | ||||||||
| + | 44 | 7 | 14.3 (10.6–18.8) | 93.3 (86.8–97.3) | 86.3 (73.7–94.3) | 27.2 (22.6–32.1) | 34.5 (29.9–39.3) | 0.043 (0.007–0.078) |
| − | 263 | 98 | ||||||
| SR_ddPCR | ||||||||
| + | 41 | 10 | 14.8 (10.8–19.5) | 92.6 (86.8–96.4) | 80.4 (66.9–90.2) | 34.6 (29.7–39.8) | 40.1 (35.5–45.2) | 0.052 (0.008–0.095) |
| − | 236 | 125 | ||||||
| U_ddPCR | ||||||||
| + | 31 | 20 | 15.8 (11.0–21.7) | 90.7 (86.1–94.3) | 60.8 (46.1–74.2) | 54.3 (49.0–59.5) | 55.1 (50.2–60.0) | 0.068 (0.001–0.134) |
| − | 165 | 196 | ||||||
| SL_ddPCR | ||||||||
| + | 29 | 22 | 27.6 (19.3–37.2) | 92.8 (89.4–95.5) | 56.9 (42.3–71.0) | 79.0 (74.4–83.0) | 76.2 (71.8–80.3) | 0.246 (0.142–0.350) |
| − | 76 | 285 | ||||||
| Sj23-LHD-ELISA# | ||||||||
| + | 23 | 28 | 22.3 (14.7–31.6) | 91.0 (89.4–95.5) | 45.1 (31.1–59.7) | 77.8 (73.2–82.0) | 73.8 (69.3–78.0) | 0.160 (0.058–0.261) |
| − | 80 | 281 | ||||||
| SjSAP4-ELISA# | ||||||||
| + | 41 | 10 | 15.6 (11.4–20.6) | 93.3 (88.0–96.7) | 80.4 (66.9–90.2) | 38.5 (33.5–43.7) | 43.7 (38.8–48.6) | 0.068 (0.021–0.114) |
| − | 222 | 139 | ||||||
CI Confidence interval, ddPCR Droplet digital PCR, The ddPCRs performed on faeces, serum, urine and saliva were designated as F_ddPCR, SR_ddPCR, U_ddPCR and SL_ddPCR, respectively. ELISA Enzyme-linked immunosorbent assay, KK Kato-Katz, POC-CCA Point-of-care circulating cathodic antigen, NPV Negative predictive value, PPV Positive predictive value.
†R cut-off value: 0.1344
#Cut-off values for ELISA assays: Sj23-LHD-ELISA, 0.2185; SjSAP4-ELISA, 0.1832 [25]