Importanza e limiti dei test di laboratorio per valutare il passaggio transplacentare di emazie fetali nel circolo materno.

The KBB acid elution test is used to assess the presence and extent of transplacental passage of fetal cells into the maternal circulation both as a diagnostic aid in detecting hemorrhage before birth and in monitoring pregnancies at risk for hemolytic disease of the newborn. However the technique is ineffective when an hereditary Hb-pathy with associated increase in HbF is present in the mother, like the HPFH, delta-beta thalassemia and other hereditary abnormal hemoglobins. A mother with HPFH and another mother with delta-beta thalassemia with false positive result of the acid-elution test are described and the need for an extension of the clinical and laboratory study in families with hereditary HbF disorder is stressed.