TABLE 1.
Performance levels of molecular diagnosis of congenital toxoplasmosis using amniotic fluid, placenta, and cord blood overall and by date of maternal infection
| Sample type and date of maternal infection | No. of cases with congenital toxoplasmosis |
No. of cases with no congenital toxoplasmosis |
Sensitivity, % (95% CL) | Specificity, % (95% CL) | Positive predictive value, % (95% CL) | Negative predictive value, % (95% CL) | Positive likelihood ratio (95% CL) | Negative likelihood ratio (95% CL) | ||
|---|---|---|---|---|---|---|---|---|---|---|
| PCR+ | PCR− | PCR+ | PCR− | |||||||
| Amniotic fluid | ||||||||||
| 0–6 WAa,b | 2 | 0 | 0 | 63 | 91 (59–100) | 100 (97–100) | 100 (69.1–100) | 99 (96.2–99.9) | NCc | 0.091 (0.014–0.59) |
| 7–15 WA | 8 | 1 | 0 | 80 | ||||||
| 16–28 WA | 21 | 6 | 0 | 87 | 78 (62–94) | 100 (96–100) | 100 (83.9–100) | 94 (88.6–98.5) | NC | 0.222 (0.11–0.45) |
| >28 WA | 12 | 0 | 0 | 11 | 100 (74–100) | 100 (72–100) | 100 (73.5–100) | 100 (71.5–100) | NC | 0 |
| Imprecise dating | 1 | 0 | 0 | 6 | NC | NC | NC | NC | NC | NC |
| All | 44 | 7 | 0 | 247 | 86 (77–96) | 100 (99–100) | 100 (92–100) | 97 (95.2–99.3) | NC | 0.14 (0.069–0.24) |
| Placenta | ||||||||||
| 0–6 WA | 1 | 0 | 2 | 44 | 100 (48–100) | 95 (91–99) | 45 (16–74.9) | 100 (96.8–100) | NC | 20.0 (9.17–43.6) |
| 7–15 WA | 4 | 0 | 4 | 69 | ||||||
| 16–28 WA | 18 | 4 | 8 | 56 | 82 (60–95) | 87 (79–96) | 69 (51.5–87) | 93 (83.8–98.1) | 0.21 (0.09–0.51) | 6.55 (3.32–12.89) |
| >28 WA | 7 | 4 | 1 | 10 | 64 (31–89) | 91 (59–100) | 87 (47.3–99.7) | 71 (41.9–91.6) | 0.40 (0.18–0.90) | 7.0 (1.03–47.81) |
| Imprecise dating | 1 | 0 | 0 | 5 | NC | NC | NC | NC | NC | NC |
| All | 31 | 8 | 15 | 184 | 79 (67–92) | 92 (89–96) | 67 (53.8–80.9) | 96 (93.0–98.7) | 0.22 (0.12–0.41) | 10.55 (6.32–17.60) |
| Cord blood | ||||||||||
| 0–6 WA | 1 | 0 | 0 | 41 | 50 (7–93) | 100 (97–100) | 100 (15.8–100) | 98 (93.3–99.8) | 0.50 (0.19–1.33) | NC |
| 7–15 WA | 1 | 2 | 0 | 62 | ||||||
| 16–28 WA | 3 | 15 | 0 | 56 | 17 (4–41) | 100 (94–100) | 100 (29.2–100) | 80 (69.4–88.4) | 0.83 (0.68–1.02) | NC |
| >28 WA | 2 | 8 | 0 | 7 | 20 (3–57) | 100 (59–100) | 100 (15.8–100) | 47 (21.1–71.9) | 0.80 (0.59–1.09) | NC |
| Imprecise dating | 0 | 1 | 0 | 3 | NC | NC | NC | NC | NC | NC |
| All | 7 | 26 | 0 | 169 | 21 (7–35) | 100 (98–100) | 100 (59.0–100) | 87 (81.9–91.4) | 0.79 (0.66–0.94) | NC |
a
WA, weeks of amenorrhea.
b
The periods 0 to 6 WA and 7 to 15 WA were distinguished due to the presence of significantly different transmission rates between them (see Table S2 in the supplemental material); however, the levels of performance of the biological tests showed no statistical differences; hence, we fused the calculations for both periods.
c
NC, not computable.