Accuracy of prenatal diagnosis for haemoglobin disorders in the UK: 25 years' experience

We have reviewed the accuracy of prenatal diagnosis for the thalassaemias a nd sickle cell disorders performed for UK residents since the service began in 1974. Prenatal diagnosis has been performed in 3254 pregnancies: 517 by fetal blood analysis, 681 by Southern blotting and 2056 by polymerase chai n reaction (PCR) methods, the majority using the amplification refractory m utation system (ARMS). The number of homozygotes diagnosed was 808 (24.8%). Twenty-five diagnostic errors have been recorded, ten arising from non-lab oratory errors (0.31%) and 15 due to technical problems associated with the diagnostic techniques. The latter group consisted of eight misdiagnoses by globin chain synthesis (1.55%), five by Southern blot analysis (0.73%) and two by PCR methods (0.10%). The data show that the accuracy of prenatal di agnosis has improved with each development of diagnostic technique, and con firms that prenatal diagnosis of beta -thalassaemia and sickle cell disorde rs by ARMS-PCR is very accurate and reliable. The overall error rate for pr enatal diagnosis by PCR methods in the UK is now 0.41%. Copyright (C) 2000 John Wiley & Sons, Ltd.