The Correlation Between the TSH Level in Neonatal Screening Test and the Prognosis of Congenital Hypothyroidism

Park, Hong Sun; Shim, Kye Shik; Choeh, Kyuchul

Abstract

PURPOSE: It is important to diagnose and treat newborn patients with congenital hypothyroidism as soon as possible because of neurodevelopmental outcome. If we can detect more severe forms of congenital hypothyroidism with neonatal screening test, the results of treatment will improve.
METHODS
Sixty-four term infants whose TSH levels in neonatal screening test had been higher than 20 micro-International Unit were recalled. Their serum levels of T3, T4, TSH and thyroid scans were checked. They were divided into two groups according to the results, in which T group had transient thyroid disease and P group had permanent congenital hypothyroidism. The TSH levels in neonatal screening test between the two groups were compared and correlated with T3, T4 and TSH levels in their serum.
RESULTS
The number of patients of T and P groups were 43 and 13 respectively. The mean TSH level of both group in neonatal screening test was 28.6 micro-International Unit/mL and 55.7 micro-International Unit/mL respectively. The mean TSH level in neonatal screening test is significantly higher in P than T group(P<0.05). If we choose 48 micro-International Unit/mL as a cutoff value, the sensitivity of detecting the P group is 77% and the specificity is 100%. The TSH levels in neonatal screening test had a positive correlation with the serum TSH levels and a negative correlation with the serum T4 levels(r=0.56 P<0.01, r=-0.53 P<0.01).
CONCLUSION
If the TSH level in neonatal screening test is greater than 48 micro-International Unit/mL, there is a greater possibility of the permanent and severe congenital hypothyroidism. So we should try to diagnose and treat them more quickly.