Flow cytometric assessment of feto-maternal hemorrhage; a comparison with Betke-Kleihauer

Objectives Assessing the number of fetal cells in the maternal circulation quantifies the volume of feto‐maternal hemorrhage, enhancing the ability to provide effective prevention of Rhesus (Rh) allommunization and appropriate fetal surveillance in cases of significant feto‐maternal hemorrhage. Methods Having developed a standard curve with maternal samples spiked with known volumes of fetal red blood cells, we used a flow cytometric method using fluorescent labeled antihemoglobin F to quantitate fetal cells in the maternal circulatory system in two groups of women undergoing chorionic villus sampling (CVS), by either biopsy forceps or cannula aspiration (n = 170 women). We compared these results with the gold standard, the Betke–Kleihauer test. Results Our results show good correlation between the flow cytometric method and the traditional Betke–Kleihauer method for fetal red cell quantitation (r2 = 0.99). Fetal red blood cells were identified in 10 women by the Betke–Kleihauer method, and in 26 women by flow cytometry. CVS was not associated with an increase in feto‐maternal hemorrhage. Conclusion Flow cytometry was both more sensitive and more timely for the quantitation of feto‐maternal hemorrhage than was Betke–Kleihauer. Copyright © 2007 John Wiley & Sons, Ltd.