title: Haematological aspects of antenatal diagnosis for thalassaemia in Britain.
abstract: The results are described of 200 antenatal diagnostic tests for haemoglobinopathies performed on samples of fetal blood obtained during the second trimester of pregnancy. Haemoglobin A synthesis in the fetus was measured by incorporation of tritiated leucine in vitro and separation of the globin chains on CM23 columns. The range of HbA synthesis detected was 3.5-8.0% in normal fetuses, 2.0-5.0% in fetuses with thalassaemia trait, and less than 1.6% in fetuses with thalassaemia major. There were eight cases in which other haemoglobinopathies were diagnosed. 29% of the pregnancies were terminated because thalassaemia major was diagnosed, and 9.5% of the remaining healthy fetuses were lost for obstetric reasons. Follow up has been possible for 96% of the 124 surviving babies and three misdiagnoses have come to light; one false positive (0.5%) and two false negatives (1%). These figures represent a first effort at antenatal diagnosis for haemoglobinopathies and it is likely that they will improve with the passage of time.
mesh_terms: D002852:Chromatography, Ion Exchange; D003951:Diagnostic Errors; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005500:Follow-Up Studies; D006441:Hemoglobin A / Q000096:biosynthesis*; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D013789:Thalassemia / Q000175:diagnosis*; D006113:United Kingdom
chemical_list: D006441:Hemoglobin A