[Neonatal screening for hypothyroidism by simultaneous determination of T4 and TSH on filter paper (author's transl)].

A simultaneous determination of T4 and TSH has been done on 48 000 new borns since January 1st of 1977 in the Midi-Pyrénées district. 15 cases of hypothyroidism have been detected, an incidence of 1/3 200 new borns. TSH values always were above 80 microU/ml; T4 values are under m-2 sigma in 11 cases, normal in 2 cases (8,8 and 9 micrograms/dl) and between -1 and - 2 sigma in 2 cases. A thyroid scanning with 123 odine or 99 Tech, has shown the absence of thyroid in 6 cases, an ectopic gland in 7 cases and a thyroid in a normal position in one case. A treatment has been possible before the first month of life in each case. The average D.Q. for the seven oldest new borns (m = 11 months) is 96. The simultaneous determination of T4 and TSH is a sensitive and specific screening method for hypothyroidism. False-negative are avoided and the number of false-positive results is reduced. All cases of hypothyroidism can be detected (primary hypothyroidism, hypothalamo-hypopituitary hypothyroidism, TBG deficiency, etc...) Then, an early and certain diagnosis is made possible (T4 low and TSH increased).