Quantitative fetomaternal hemorrhage assessment with the use of five laboratory tests.

ABSTRACT

INTRODUCTION: In various countries, standard doses of anti-D IgG used for postpartum immunoprophylaxis of hemolytic disease of fetus and newborn (HDFN) vary from 100 µg to 300 µg. There are also different regulations concerning FMH assessment, and opinions about applicable tests are inconclusive. METHODS: Three flow cytometry tests (FCTs) with anti-D, anti-HbF, anti-HbF+CA antibodies, and two modifications of microscopic Kleihauer-Betke test (KBT) were used. RESULTS: In all artificial mixtures with known concentrations, FCTs and KBT with counting 10 000 RBCs had similar satisfying sensitivity and specificity. KBT with counting 2000 RBCs had to be disqualified because of significant discrepancies between expected and measured values of FMH. The test procedure with anti-D was easier and shorter than the remaining tests, but it can be only used for FMH assessment in RhD-negative mothers with RhD-positive newborns. In one clinical sample, it was impossible to distinguish fetal RBCs from maternal F cells in KBT and FC with anti-HbF but other tests were useful. CONCLUSION: In the four tests, correlation between expected and obtained results was appropriate (CCC Ì´1). Each test had some advantage and limitation in any clinical situation. Therefore, it is best to have opportunity to perform two or three assays in the laboratory.