Measurement of feto-maternal haemorrhage: a comparative study of three Kleihauer techniques and tow flow cytometry...

In the UK a Kleihauer test is routinely performed on all RhD-negative women after the birth of an RhD-positive child to ensure that an adequate dose of anti-D immunoglobulin is given. The results of Kleihauer testing are interpreted to assess the volume of any feto-maternal haemorrhage and additional anti-D immunoglobulin is administered if necessary. A similar procedure is followed ante-natally when incidents occur known to be associated with alloimmunization. The performance of Kleihauer tests is difficult to standardize and there can be problems in interpreting the volume of feto-maternal haemorrhage. The use of flow cytometry to measure feto-maternal haemorrhage is reported to give more accurate and reliable results. This study compared three different Kleihauer methods and two different flow cytometry techniques all performed using the same maternal sample and within a single laboratory. The results demonstrated variability between the Kleihauer tests used and also in the flow cytometry measurements. A well-performed Kleihauer test would still appear to be useful as a screening technique for detection of feto-maternal haemorrhage. However, accurate quantitation of size of feto-maternal haemorrhage is more reliably determined by flow cytometry.