Diagnosis and Follow-up of Patients With Subclinical Hypothyroidism
Diagnosis and Follow-up of Patients With Subclinical Hypothyroidism
Long term follow-up of the patients with delayed TSH elevation or subclinical hypothyroidism
 has been seldom reported. The purpose of this study was to explore the diagnostic criteria
 for subclinical hypothyroidism and the initial dosage of L-thyroxine through long-term follow
 up for infants with subclinical hypothyroidism ，and evaluate the curative effect.
Long term follow-up of the patients with delayed TSH elevation or subclinical hypothyroidism
 has been seldom reported. The purpose of this study was to explore the diagnostic criteria
 for subclinical hypothyroidism and the initial dosage of L-thyroxine through long-term follow
 up for infants with hyperthyrotropinemia，and evaluate the curative effect.All live-born
 neonates in province took part in the screening program from October, 1999 to September
 ,2006. Laboratory tests are performed as a time resolved fluoro-immunoassay (TRFIA). TSH is
 measured with a cut-off > 9 mU/L. The diagnostic standard for subclinical hypothyroidism was:
 TSH ≥ 20 mU/L, T3 and T4 normal or low-normal ,or TSH > 5.6 mU/L and < 20 mU/L on initial
 determination and on follow-up or TSH levels increase on follow-up and/or gradually declining
 T4 levels.L-Thyroxine was administered for substitution therapy. After 2 years
 therapy，allround evaluation was performed. Compare the correlation to effects with different
 level of TSH、starting time of therapy and environment. Compare the effects between
 subclinical、temporary and permanent hypothyroidism.
Inclusion Criteria:

 -  The diagnostic standard for manifest hypothyroidism and subclinical hypothyroidism was
 defined as follows:

 -  Hypothyroidism - TSH > 40 mU/L and T3 and T4 below the reference range or TSH >
 40 mU/L, T3 normal and T4 below the reference range [2]

 -  Subclinical hypothyroidism - TSH ≥ 20 mU/L, T3 and T4 normal or low-normal or TSH
 > 5.6 mU/L and < 20 mU/L on initial determination and on follow-up or TSH levels
 increase on follow-up and/or gradually declining T4 levels.