Neonatal screening for congenital hypothyroidism in an Italian Centre: a 5-years real-life retrospective study

Congenital hypothyroidism is an endocrine disease with a significant incidence in the general population (1:2000-1:3000 newborns in Italy) and a different geographical distribution, partially explained by endemic iodine deficiency, genetic traits and autoimmune thyroid diseases.

Aims of this study are: to evaluate the incidence of positive neonatal blood spot screening for CH in western Sicily, identified by the screening centre of the Children Hospital "G. Di Cristina", ARNAS, Palermo; to evaluate the impact of a lower TSH cutoff in the neonatal blood spot screening for CH.

The TSH threshold of the neonatal screening was established as ≥6 mU/L of whole blood. We analysed the screening centre data in the period January 2013-April 2018, for a total number of 85.373 babies (45.7% males; 54.3% females).

4.082 Babies (4.8%) required a second screening. Among these, 372 (0.44%) were out of range. The diagnosis of congenital hypothyroidism (CH) was confirmed in 182 babies (0.21%). 77/372 newborns (20.7%) with confirmed high TSH levels showed whole blood TSH levels ≥6 - < 7 mU/L. In synthesis, 48.9% of the out of range re-testing had a confirmed diagnosis of CH.

The reduction of TSH cutoff to 6 mU/L allowed to identify 77/372 neonates (20.7%) with confirmed out of range TSH, otherwise not recruited by the previously employed TSH cutoff.