Comparison of quantitative acid-elution technique and flow cytometry for detecting fetomaternal hemorrhage

A study of the Kleihauer-Betke acid-elution technique for quantitating fetomaternal hemorrhage was performed to assess intra- and inter-technologist accuracy and precision as well as to delineate the statistically valid domain of the test as usually performed. The results were then compared to a parallel study quantitating fetomaternal hemorrhage by flow cytometry. Additionally, a statistical model for estimating efficacy of treatment with Rh immune globulin in the prevention of pregnancy-associated Rh(D) isoimmunization was developed. The results indicate that the acid-elution technique can be performed in a reproducible manner with acceptable accuracy and precision with whole blood fetomaternal hemorrhages 25 ml and higher if a background correction for false positive identification of fetal cells is included. Flow cytometric determination reveals significantly increased accuracy in comparison to the corresponding Kleihauer-Betke results.