A 7‐year experience with low blood TSH cutoff levels for neonatal screening reveals an unsuspected frequency of congenital hypothyroidism (CH)

Summary Context The guidelines of the National Academy of Clinical Biochemistry advocated the use of low bloodspot TSH (b‐TSH) threshold for newborn screening of congenital hypothyroidism (CH). The impact generated by the application of this indication is largely unknown. Objective To determine the impact on CH epidemiology and classification generated by the introduction of low b‐TSH cutoff. Design Retrospective study of 629,042 newborns...