Screening programmes for foetomaternal alloimmune thrombocytopenia.

Screening to detect pregnancies at risk of severe thrombocytopenia due to Foetomaternal alloimmunisation to Human Platelet Alloantigens (FAIT) is not yet a standard of care. Screening may be performed antenatally with the possibility of early intervention/therapy. Post natal measurement of cord platelet count may not always prevent fetal damage but may detect severe thrombocytopenia from other causes. Assessment of FAIT screening against World Health Organisation standards for screening programmes helps define areas where knowledge is still lacking and where research effort should be directed. Limitations to screening have been lack of reliable assays for typing and antibody detection, a limited understanding of the relationship between the presence of alloantibodies and clinical disease, inability to predict non-invasively which cases will have a severe outcome, and controversy as to which antenatal therapy is optimal for cases at high risk of a poor outcome.