Are IGF-I and IGF-BP3 useful for diagnosing growth hormone deficiency in children of short stature?

Background: The diagnosis of growth hormone deficiency (GHD) is based on clinical and auxological characteristics combined with the results of growth hormone provocation tests.
Aim: To evaluate the utility of IGF-I and IGF-BP3 serum levels in the diagnosis of GHD among children of short stature.
Subjects/methods: We recruited 207 short pre-pubertal children and divided them into two groups. One group consisted of 70 children (mean age 7.93 +/- 2.35 SD) with a growth hormone (GH) response on two provocative tests of < or = 8 ng/ml, while the other group contained 137 children (mean age 7.92 +/- 2.11 SD) with a peak GH value of > 8 ng/ml. Serum IGF-1 and IGF-BP3 levels were determined in the two groups.
Results: The difference in serum IGF-I between the two groups was not significant (p= 0.26), while the difference in IGF-BP3 between the two groups was statistically significant (p= 0.004). The performance of serum IGF-1 and IGF-BP3 as a diagnostic tool, expressed as AUC by ROC analyses, was quite low.
Conclusion: Neither IGF-I nor IGF-BP3 are an adequate substitute for the stimulus test in the diagnosis of growth hormone deficiency among children of short stature.