Flow cytometry in diagnosis and management of large fetomaternal haemorrhage

Abstract

Aims-To evaluate an indirect immunofluorescence flow cytometry technique in a series ofpatients with large fetomaternal haemorrhage (FMH). Methods-Patient samples identified by Kleihauer testing in local laboratories as having FMH >4 ml were sent for flow cytometric analysis. In a proportion of cases the mothers received anti-D immunoglobulin prophylaxis according to the flow cytometer estimate of FMH volume. Results-Forty three cases of FMH were studied prospectively. The correlation between Kleihauer and flow cytometry results was poor. In 38 (88%) cases the size of FMH quantitated by flow cytometry was lower than that estimated using the Kleihauer technique. In 13 (30%) cases no Rh D immunoglobulin positive cells were detected by flow cytometry. Centralised review ofthe original Kleihauer films using a calibrated microscope resulted in improved, but still suboptimal correlation with flow cytometry results. In 15 cases anti-D immunoglobulin was given according to the flow cytometer estimation ofFMH size, resulting in a 58% reduction in the amount of anti-D immunoglobulin given. None of the patients were immunised when tested six months later. Conclusions-Flow cytometry is helpful for the accurate quantitation and management of patients with large FMH and in cases where the presence of maternal haemoglobin F containing cells renders the Kleihauer technique inaccurate. Worthwhile reductions in the use of anti- D immunoglobulin can be achieved.