The purpose of this study was to validate the growth hormone releasing hormone (GHRH) plus arginine (GHRH+arg) stimulation test and it´s cut-off limits for diagnosis of adult growth hormone deficiency using the growth hormone (GH) Immulite 2000 Xpi assay calibrated against the IS 98/574 from the World Health Organization. A specific aim was to study the effect of gender and age on the peak GH response in the GHRH+arg test

Adult growth hormone deficiency (AGHD) is a clinical entity including increased abdominal fat mass, decreased muscle mass, low bone density and adverse effects on quality of life and cardiovascular morbidity. These signs are nonspecific, and accurate diagnosis with laboratory tests in needed.

The GHRH+arg test is used to diagnose AGHD, but the cut-off values vary based on controls used. At moment consensus cut-off criteria are BMI specific, but gender and age may also affect the GH response in the GHRH+arg.

Inclusion Criteria:

for health patients:

1. age 20-60 years,
2. no symptoms indicative of disease.

for patients:

1. age 16-90 years
2. previous pituitary disease
3. suspicion of growth hormone deficiency

Exclusion Criteria:

for healthy controls:

1. pregnancy,
2. a known or suspected disease,
3. any symptoms indicating disease
4. use of medication