SCREENING CRITERIA FOR BETA-THALASSEMIA TRAIT IN PREGNANT - WOMEN

Aims-To establish suitable screening criteria for beta thalassaemia tr ait during pregnancy using an automated blood counter incorporating li ght scattering technology. Methods-Pregnant women (n = 857) at a Londo n antenatal clinic were investigated for beta thalassaemia trait if th e Technicon H.2 full blood count showed either a mean corpuscular volu me (MCV) < 85 f1 or a mean corpuscular haemoglobin (MCH) < 27 pg. Resu lts were then analysed to establish which of these variables was more suitable for screening and to determine suitable cut off points for ca lculating the haemoglobin A, percentage. Results-The MCH was superior to the MCV for thalassaemia screening as it was a more stable measurem ent and fewer unnecessary tests were performed. A MCH less than 27 pg is a suitable cut off point for screening. This screening criterion wa s equally applicable to a Coulter impedance counter. Conclusions-Pregn ant women presenting at an antenatal clinic with a A ICH < 27 pg shoul d be investigated further to confirm or exclude a diagnosis of beta th alassaemia trait.