Table 2.
Prevalence of Malaria Infection in Peripheral Blood at Different Time Points in Pregnant Ghanaian Women and Sensitivity and Specificity of an Rapid Diagnostic Test at These Time Points
| Gravidity | Number Tested | Number Positivea | % Positive by PCR or Blood Slide (95% CI) | PCR or Microscopy/RDT Result |
RDT Sensitivity % | RDT Specificity % | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| +/+ | +/− | −/+ | −/− | |||||||
| Peripheral blood | ||||||||||
| First ANC Visit | All | 592 | 347 | 58.6 (54.6, 62.5) | 308 | 39 | 23 | 222 | 88.8 (85.0, 91.9) | 90.6 (86.2, 94.0) |
| Primigravidae | 317 | 203 | 64.0 (58.6, 69.2) | 193 | 10 | 15 | 99 | 95.1 (91.1, 97.6) | 86.8 (79.2, 92.4) | |
| Secundigravidae | 272 | 142 | 52.2 (46.2, 58.1) | 113 | 29 | 8 | 122 | 79.6 (72.0, 85.9) | 93.8 (88.2, 97.3) | |
| Second ANC Visit | All | 491 | 129 | 26.3 (22.6, 30.4) | 108 | 21 | 39 | 323 | 83.7 (76.2, 89.6) | 89.2 (85.6, 92.2) |
| Primigravidae | 265 | 74 | 27.9 (22.8, 33.7) | 66 | 8 | 28 | 163 | 89.2 (79.8, 95.2) | 85.3 (79.5, 90.0) | |
| Secundigravidae | 224 | 55 | 24.6 (19.3, 30.7) | 42 | 13 | 10 | 159 | 76.4 (63.0, 86.8) | 94.1 (89.4, 97.1) | |
| Third ANC Visit | All | 384 | 84 | 21.9 (18.0, 26.3) | 65 | 19 | 43 | 257 | 77.4 (67.0, 85.8) | 85.7 (81.2, 89.4) |
| Primigravidae | 201 | 51 | 25.4 (19.8, 31.9) | 40 | 11 | 27 | 123 | 78.4 (64.7, 88.7) | 82.0 (74.9, 87.8) | |
| Secundigravidae | 182 | 32 | 17.6 (12.7, 23.9) | 24 | 8 | 16 | 134 | 75.0 (56.6, 88.5) | 89.3 (83.3, 93.8) | |
| Delivery | All | 158 | 35 | 22.2 (16.3, 29.4) | 17 | 18 | 17 | 106 | 48.6 (31.4, 66.0) | 86.2 (78.8, 91.7) |
| Primigravidae | 80 | 20 | 25.0 (16.6, 35.9) | 11 | 9 | 11 | 49 | 55.0 (31.5, 76.9) | 81.7 (69.6, 90.5) | |
| Secundigravidae | 78 | 15 | 19.2 (11.8, 29.7) | 6 | 9 | 6 | 57 | 40.0 (16.3, 67.7) | 90.5 (80.4, 96.4) | |
The number of women with missing gravidity status was first visit, 3; second visit, 2; third visit, 1; delivery, 0.
Abbreviations: ANC, antenatal clinic; CI, confidence interval; PCR, polymerase chain reaction; RDT, rapid diagnostic test.
a Positivity in peripheral blood is defined as either a positive PCR result or a positive blood slide.