Screening for congenital hypothyroidism involves looking for high concentrations of neonatal blood TSH - this test discriminates better than low blood thyroxine, although it accepts a failure to recognise congenital pituitary hypothyroidism.
The screening works in parallel to the PKU screening program, so allowing it to be implemented at minimal extra cost and organisation.
The prevalence of this condition appears to have increased since the introduction of the program, and it is hard to decide if this is a true increase in prevalence or a reflection of overdiagnosis or previous underdiagnosis.
The test is repeated in those being treated with a withdrawal of the treatment at one year.
Last reviewed 01/2018