Thyrotropin (TSH) secretion in L-thyroxine treated children: assessment by a ultrasensitive TSH immunoradiometric assay.
The clinical usefulness of the measurement of basal TSH by an ultrasensitive assay (IRMA) versus the TRH test has been challenged in 49 children treated with L-thyroxine. They were given suppressive or replacement therapy depending on the underlying disease. An absent response of TSH to TRH could be predicted from a basal TSH value less than 0.1 mU/l in 88.8% of the cases, while only in 77.7% from a basal TSH value = 0.1 mU/l. A basal TSH value found in the range of the normal children always predicted a normal TRH test. We conclude that a sensitive TSH assay has some clinical application in monitoring L-thyroxine therapy, but can not absolutely replace the TRH test.
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy*; D007223:Infant; D008297:Male; D011863:Radioimmunoassay; D013963:Thyroid Hormones / Q000097:blood; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000188:drug therapy*; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone; D014443:Tyrosine / Q000627:therapeutic use*
D013963:Thyroid Hormones; D014443:Tyrosine; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin