Table 3 Effectiveness of fetal blood sampling as a stimulation/diagnostic test for the condition of fetal acidemia i.e. abnormal value in scalp blood or low pH in umbilical artery blood. Lactate in mmol/L
| Â | No acceleration Test positive | + Acceleration Test negative | Sensitivity % (95% CI) | Specificity % (95% CI) | LHR+ (95% CI) | LHR- (95% CI) |
|---|---|---|---|---|---|---|
Whole cohort not divided by time from FBS to delivery, n = 385 | 245 | 140 |  | |||
Scalp lactate < 4.2 | 161 | 120 | 79 (69.4–86.6) | 42.7 (36.9–48.7) | 1.38 (1.19–1.59) | 0.49 (0.33–0.74) |
Scalp lactate ≥4.2 | 75 | 20 |  |  |  |  |
Scalp lactate ≤4.8 | 194 | 125 | 73.7 (60.3–84.5) | 39.2 (33.8–44.8) | 1.21 (1.01–1.45) | 0.67 (0.43–1.06) |
Scalp lactate > 4.8 | 42 | 15 |  |  |  |  |
FBS to delivery ≤20 min n = 128 | 108 | 20 |  | |||
Scalp lactate < 4.2 | 52 | 8 | 81.5 (67–90.1) | 13.3 (5.9–24.6) | 0.94 (0.81–1.10) | 1.38 (0.61–3.15) |
Scalp lactate ≥4.2 | 53 | 12 |  |  |  |  |
Scalp lactate ≤4.8 | 71 | 9 | 75.6 (60.5–87.1) | 11.3 (5.3–20.3) | 0.85 (0.71–1.02) | 2.17 (0.97–4.84) |
Scalp lactate > 4.8 | 34 | 11 |  |  |  |  |
pH ≤ 7.1 | 19 | 4 | 82.6 (61.2–95.1) | 16 (9.4–24.7) | 0.98 (0.8–1.21) | 1.09 (0.4–2.95) |
pH > 7.1 | 84 | 16 |  |  |  |  |