Serum concentration of free T3, free T4 and TSH in healthy children.
OBJECTIVE
It is rare that manufacturers report age-related FT3, FT4 and TSH normal ranges in healthy children.


METHODS
Using a solid phase time-resolved fluoroimmunometric method, we determined serum FT3, FT4 and TSH in 3,360 healthy children, age 2-16 years, that we grouped into two age ranges (2-7 yr and 9-16 yr).


RESULTS
Boys' and girls' mean serum thyroid hormone values substantially overlap in all age groups. In the age range 2-7 yr, FT3, FT4 and TSH values were 0.10-0.67 ng/dl (mean 0.37 ng/dl), range 0.45-2.29 ng/dl (mean 1.18 ng/dl) and 0.10-5.9 microU/ml (mean 2.2 microU/ml), respectively. In the age range 9-16 yr, FT3, FT4 and TSH values were 0.11-0.53 ng/dl (mean 0.35 ng/dl), 0.69-1.69 ng/dl (mean 1.07 ng/dl) and 0.20-6.1 microU/ml (mean 2.3 pU/ml), respectively.


CONCLUSIONS
Our results represent a useful set of reference values in children and can help physicians in the management of thyroid diseases.
Cioffi
M
M
Institute of General Pathology and Oncology, Faculty of Medicine, Second University of Naples, Italy. rialab@usa.net
Gazzerro
P
P
Vietri
M T
MT
Magnetta
R
R
Durante
A
A
D'Auria
A
A
Puca
G A
GA
Molinari
A M
AM
D000293:Adolescent; D000375:Aging / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D012016:Reference Values; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine