SCREENING CRITERIA FOR BETA-THALASSEMIA TRAIT IN PREGNANT - WOMEN

Aims-To establish suitable screening criteria for beta thalassaemia trait during pregnancy using an automated blood counter incorporating light scattering technology. Methods-Pregnant women (n = 857) at a London antenatal clinic were investigated for beta thalassaemia trait if the Technicon H.2 full blood count showed either a mean corpuscular volume (MCV) < 85 f1 or a mean corpuscular haemoglobin (MCH) < 27 pg. Results were then analysed to establish which of these variables was more suitable for screening and to determine suitable cut off points for calculating the haemoglobin A, percentage. Results-The MCH was superior to the MCV for thalassaemia screening as it was a more stable measurement and fewer unnecessary tests were performed. A MCH less than 27 pg is a suitable cut off point for screening. This screening criterion was equally applicable to a Coulter impedance counter. Conclusions-Pregnant women presenting at an antenatal clinic with a A ICH < 27 pg should be investigated further to confirm or exclude a diagnosis of beta thalassaemia trait.