Screening for congenital hypothyroidism in Maltese newborns using cord blood

Abstract

Routine screening for congenital hypothyroidism (CHT) has been introduced because clinical features of CHT may not be evident before the baby is a few weeks old and treatment at this stage may already be too late. Since a newborn testing programme employing liquid cord blood for other conditions had already been developed in the University of Malta and the Department of Health, we explored the possibility of implementing newborn thyroid testing using liquid cord blood. A similar programme had been implemented successfully in Finland and Philadelphia. Between September 1989 and August 1995 around 32,000 newborns were tested. This is nearly complete ascertainment. Preliminary testing was by radioimmunoassay for TSH. The sera of those with TSH levels more than 13mU/l were further tested for free T4. If the free T4 level was below 12 pmol/l, the babies were recalled for clinical evaluation and repeat testing. Other babies were recalled for technical reasons, giving a total recall rate of 3.88%. CHT was identified in seven newborns and treatment started within 3 weeks of delivery. One baby was reported normal on screening but was suspected to have CHT on clinical grounds at 3 weeks of age, confirmed biochemically. The incidence of CHT in Malta is therefore 1 in 4500.