Assessment of noninvasive, percutaneous hemoglobin measurement in pregnant and early postpartum women

PURPOSE: Using the Pronto-7® analyzer, we measured percutaneous hemoglobin (SpHb) noninvasively in pregnant and early postpartum women, and assessed the accuracy of the measurements by comparing them with laboratory measurements of hemoglobin. METHODS: We obtained SpHb measurements from 193 pregnant women, 269 early postpartum women, and 76 nonpregnant women. A laboratory total hemoglobin (tHb) measurement, from venous blood sampling, was obtained immediately prior to the SpHb measurement. The total number of measurements obtained from the nonpregnant, pregnant, and postpartum women was 76, 438, and 347, respectively. RESULTS: The mean biases (SpHb − tHb) among the nonpregnant, first trimester, second trimester, third trimester, and early postpartum women were −0.20, 0.19, 1.01, 1.32, and 1.10 g/dL, respectively. The Bland–Altman comparison showed neither the tendency of a fixed bias nor proportional biases among the measurements in the category of nonpregnant and first trimester women. But in the second and third trimester and postpartum category, a significant fixed bias was noted, without any tendencies of proportional bias. CONCLUSION: In this study, we found higher hemoglobin values with the Pronto-7 analyzer than were measured in the laboratory. We consider that the device has certain limitations in obstetrical utility and requires further modifications for use in the perinatal period.