Laboratory methods give more accurate measurement of blood loss in the
postpartum period than visual estimation. In order to evaluate a labo
ratory method used to quantify blood loss postpartum, blood lost at gy
necological operations was collected in a measuring bottle. The measur
ed amount of blood (50-1,000 mi) was then poured onto absorbent paper
towels and sanitary pads, in order to mimic conditions when measuring
blood loss in clinical trials in the postpartum period. The amount of
blood absorbed onto the absorbent paper and sanitary pads was measured
by a rapid method of automatic extraction and photometric measurement
of alkaline hematin. The study shows that the method provides a relia
ble and accurate means of measuring blood loss. The error in each case
was less than 10% with an intraclass correlation coefficient of almos
t 1.