Role of flow cytometry in mothers with hereditary persistence of fetal haemoglobin.

摘要

The Kleihauer-Betke test is commonly performed to assess fetomaternal haemorrhage. It is an acid elution test, which relies on the stability of fetal haemoglobin exposed to a moderate acid. The relatively unstable maternal haemoglobin is washed out of the erythrocytes and therefore the remaining cells containing fetal haemoglobin stain darkly and are easily identified in contrast to the maternal 'ghosts' under light microscopy. This test could be positive in genuine cases of fetomaternal haemorrhage or in mothers with hereditary persistence of fetal haemoglobin (HPFH). It is essential to differentiate between the two as the former could be life-threatening to the fetus, while the latter has no significance. The Kleihauer technique is ineffectual in HPFH, and in a pregnant woman who is Rh(D)-negative, diagnostic confusion with a large fetomaternal bleed could lead to inappropriate administration of large doses of anti-D immunoglobulin. Alternatively, inability to quantify fetomaternal haemorrhage could result in insufficient anti-D administration and subsequent Rh(D) sensitization (Patton et al. 1990).