Distribution of T4 TSH values in children - the Shifa experience

ABSTRACT

To evaluate the distribution of Thyroxin [T4] and Thyroid Stimulating Hormone [TSH] values in children of various age groups attending our hospital. Subject and We have retrospectively reviewed the T4, TSH levels recorded at our hospital in children from birth to 5 years and evaluated the reference intervals for T4 TSH amongst different ages. Non parametric methods were used to establish a 97.5th, 95th, 50th, 5th and 2.5th centiles. In T4 [n=1148] and TSH [n=1142] samples reviewed a TSH surge following delivery showed a sharp decline in the first 4 days of life. This was followed by a more gradual downward trend. Data on T4 estimations showed a similar but more gradual downward trend in advancing age groups. The 5th - 95th centile reference range for TSH showed values between 1.7--22.5 [0--4days; n=992], 0.6--13.3 [5--7days; n=36], 0.9--14.0 [1week--1 month; n=38], 0.5--13.6 [1month-1 year; n=38] and 0.4--12.8 [1--5 years; n=38] microIU/mL. The 5th - 95th centile reference range for T4 showed values between 10.7-25.0 [0-4days; n=995], 6.5--20.4 [5--7 days; n=35], 8.0-18.1 [1week--1month; n=38], 6.0--16.1 [1month--1year; n=41], 6.9-15.3 [1--5 years; n=39] micro gm/dl. We recommend using separate T4 and TSH reference values for children in different age groups. Further large-scale studies should be done in Pakistan to establish these reference values within age groups. A national center for neonatal thyroid screening is highly recommended