The relationship between recall rate and the incidence of congenital hypothyroidism in the screening program for neonatal hypothyroidism in Arak, 2006

Oetection of congenital hypothyroidism (CH) in Arak has begun since 2006. The aim of this study was to investigate on recall rate (RR) and the incidence of this disease in Arak. In this descriptive study, according to the national screening program for CH in Iran, heel blood samples of 3-5 day- old neonates were taken on special filter paper and TSH values were measuned using ELISA method. TSH values bigger than 5mu/lit were recalled and thyroid function tests (TSH, T4 and T3RUP) were done on venous blood samples and assayed using ELISA method. Neonates with TSH values >10 mu/lit, T4<6.5 ug/dl were viewed as patients. Data related to neonates born up to the end of March 2009 were recorded in special forms. Of 25685 screened neonates, 608 newborns were recalled. RR was estimated to be 2.36%. TSH values in 3.78% were less than 5, in 83.55% between 5-9.9, in 7.56% between 10-19.9 and in 5.09% more than or equal to 20. Eighty six neonates had CH (1/300 live births). Disease rate in recalled neonates was 14.2%. In 80.26 percent of neonates, sampling was done between 3-5 days while the times of sampling in 18.5 and 1.1 percents of the newborns were in days 6-21 and after day 22, respectively. The incidence of CH in Arak is remarkably higher than national and international rates. RR in Arak is higher than the national but lower than the international rates. Also, the ratio of the disease to the recalled neonates is low.