Serum IGF-1 and IGFBP-3 Levels for Normal Thai Children and their Usefulness in Clinical Practice
SUTTIPONG WACHARASINDHU, M.D., M.R.C.P. (UK)*, KATHAREE CHAICHANWATANAKUL, B.Sc.*, SUPAWADEE LIKITMASKUL,M.D.*, KITTI ANGSUSINGHA,M.D.*, LUEPORN PUNNAKANTA, M.D.*, CHANIKA TUCHINDA, M.D., F.A.A.P.*
Affiliation : * Division of Endocrinology, Department of Pediatrics, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
Abstract
Serum IGF-I and IGFBP-3 levels are growth hormone (GH) dependent and reflect the
endogenous GH secretion.
Two hundred and forty-four healthy children were evaluated for serum IGF-I and
IGFBP-3 levels and then the age-defined normal values for Thai children were constructed. The
results showed that the serum IGF-1 and IGFBP-3 levels were age dependent, gradually increased
from birth and reached the peak values around the age of 14-16 years.
In addition, we studied the IGF-1 and IGFBP-3 values in 28 GH deficient children and 26
normal variant short stature (NVSS) by using our normal constructed values as the reference.
To minimize the influence of age, both IGF-1 and IGFBP-3 values were transformed to standard
deviation score (SDS). In clinical practice, we recommend using the IGF-1 SDS and IGFBP-3
SDS of -1 and -1.3 respectively as a cut-off point to discriminate between GH deficiency and
NVSS to avoid risky GH provocative tests and unnecessary GH replacement with the sensitivity
of 71 per cent and the specificity of 92 per cent.
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