Establishment of reference values for endocrine tests--part V: acromegaly.
BACKGROUND
Plasma insulin-like growth factor 1 (IGF-1) and the response of growth hormone (GH) to oral glucose are frequently used in the evaluation of patients suspected of acromegaly. Because of the implementation of new assay methodology for GH and IGF-1, we have established the reference values for these tests, as well as for urinary GH excretion.


METHODS
From the general population, 50 subjects were recruited, equally distributed according to sex and age between 20 and 70 years. Two consecutive 24-hour urine samples were collected to determine urinary GH. Plasma IGF-1 was measured as well as the GH response during an oral glucose tolerance test (OGTT) with 100 g glucose. Basal plasma IGF-1 was also measured in 250 subjects recruited likewise from the general population who had participated in previous studies on reference values.


RESULTS
The following reference ranges were established: urinary GH < 5-46 microU/24 h; nadir GH after OGTT < or =1.5 mU/l for males and < or =2.0 mU/l for females. IGF-1 was divided into age groups: 20-30 years 8-61 nmol/l; 31-40 years 8-41 nmol/; 41-50 years 7-36 nmol/l; 51-60 years 5-37 nmol/l; and 61-70 years 7-27 nmol/l.


CONCLUSIONS
We have established reference values with state-of-the-art assay methodology for the diagnostic tests frequently used in the evaluation of patients suspected of acromegaly.
Endert
E
E
Department of Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands. e.endert@amc.uva.nl
van Rooden
M
M
Fliers
E
E
Prummel
M F
MF
Wiersinga
W M
WM
D000172:Acromegaly / Q000175:diagnosis* / Q000378:metabolism; D000328:Adult; D000367:Age Factors; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D005260:Female; D005951:Glucose Tolerance Test; D019382:Human Growth Hormone / Q000097:blood* / Q000652:urine; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D012016:Reference Values
D015415:Biomarkers; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I