How is it Diagnosed?
Growth Hormone Deficiency (GHD) is diagnosed using a combination of clinical
assessment, growth monitoring, laboratory tests, and imaging. In children, the condition
is often suspected when there is significant short stature, poor growth velocity, or
delayed bone age.
An initial evaluation includes plotting the child's growth on standardized growth charts
and performing a bone age X-ray, typically of the left hand and wrist, to compare
skeletal maturity with chronological age. Serum insulin-like growth factor-1 (IGF-1) and
IGF-binding protein-3 (IGFBP-3) are measured, as these are GH-dependent markers.
Low levels may indicate GHD but are not conclusive.
Because GH is secreted in pulses, a single random GH level is not diagnostic. Therefore,
stimulation tests are necessary. These include insulin tolerance test (ITT), clonidine, or
arginine stimulation tests to provoke GH release. A peak GH level below the defined
cutoff (often <10 ng/mL in children) confirms the diagnosis.
MRI of the brain, especially the hypothalamic-pituitary region, helps identify structural
causes such as pituitary hypoplasia or tumors. In adults, GHD is suspected based on
symptoms like reduced muscle mass, fatigue, and central obesity, often confirmed by
similar hormone stimulation tests.