RESUMEN
Although major beta-thalassemia prevention and control program is one of the most successful programs in genetics field, there are new cases of major beta-thalassemia due to laboratory errors. So the laboratory quality control [QC] is very important to diagnose carriers in preventive programs. At present, there is not a distinct and measurable index for function assessment and comparison in screening laboratories; this urged us to create an objective, measurable and explicit index for health care givers. For this purpose, we compared the function of screening labs in districts of Isfahan Province. In this cross-sectional study, we collected the data from "pre-marriage screening program" in 18 districts [19 screening labs] covered by Isfahan University of Medical Sciences from 2006 to 2008. The percentage rates of "screened males with low blood indexes" in every 3 months [P index] were assessed; then, the average and coefficient variants in duration of 3 years were calculated with excel software. Based on these findings, "screening labs' functions" were assessed and compared. The least "CVs of P index" within 19 labs were found to be in Mobarakeh laboratory [10.4%] and Provincial reference lab [10.9%], respectively. The highest CVs were found in Khour [76.3%] and Tiran and Karvan labs [58.2%], respectively. The P index average in all centers was 14% [13.9% in reference lab] with the highest being in Mobarakeh[24.2%] and the lowest in Khour[8.8%]. Whereas the number of marriage candidates in each screening lab is relatively stable, the centers with the highest CV value of P index are probably lower in function level as compared with the centers with the lowest CV value of P index [as in reference screening lab]. CV of P index may be a good evidence for quality of "screening lab function" and should be evaluated annually. The screening labs with high CV of P index need more attention and evaluation