The pros and cons of the fourth revision of thalassaemia screening programme in Iran

Abstract

Objective: To evaluate the repercussions of recent changes to the cut-offs used in the first screening step of the pre-marital screening programme for thalassaemia prevention in Iran. Methods: The profiles of 984 subjects referred to a genetic laboratory, and the tests of 242 parents of children with thalassaemia major were assessed for red blood cell ( RBC) indices, haemoglobin ( Hb) A2 levels and results of Hb electrophoresis. Results: Of 407 suspected thalassaemia minor ( STM) cases, 18 proved positive for thalassaemia minor on molecular analysis ( 18/407, confidence interval 2.6-6.9). If the revised screening cut-offs had been used to determine who would undergo molecular analysis, two of these cases would not have been identified. Only 4.4 of suspected cases with lower than normal RBC indices ( mean corpuscular volume <80 fl and mean corpuscular Hb <27 pg) and HbA2 (<3.5) were diagnosed with thalassaemia minor. Conclusion: The thalassaemia major prevention programme is performed in two separate steps. One step involves the screening of subjects and identification of b-thalassaemia minor, suspected cases for thalassaemia minor ( STM), and normal subject groups. The other step concerns the identification of thalassaemia minor in the STM group. Changing the cut-offs at the first screening step does not result in significant improvement from an economic view, and is associated with significant risk at the second screening step.