Pathology | Eastern Health

Test & Collection Guide

Growth Hormone Suppression Test

Ordering information:

Dynamic test requiring blood draws at 30 minute interals for 2 hours (5 samples total, for both growth hormone and glucose.

75g glucose (in 300mL solution) administered orally immediately after the first blood draw.

Alternate names:

GTGH, GTT with Growth hormone

Laboratory:

Biochemistry

Test Code:

GTGH

Specimen types:

Serum
Plasma

Container types:

Fluoride/oxalate tube (grey)
Serum tube with gel

Collection Instructions:

Transport specimen at Room Temperature to lab

Timepoints:

- 5 min: First collection: Glucose, GH and IGF-1

0 min: 75g glucose adminsitered (as per usual OGTT)

+ 30 min: Second collection: GH and Glucose.

+ 60 min: Third collection: GH and Glucose.

+ 90 min: Fourth collection: GH and Glucose.

+ 120 min: Fifth collection: GH and Glucose.

Keep samples with patient until end of test, then send to lab together. Growth Hormone is stable for 8 hours at room temperature.

Send samples together at end of test.

Minimum Adult Volume:

2 mL

Notes:

2mL per Serum sample, 2mL per flox sample.

Frequency:

Twice weekly

Result Turnaround Time:

4-6 days

Reference Interval:

For diagnostic purposes, negative test if GH < 1.0 at any timepoint.

For monitoring purposes, neg test if GH < 0.5 at any time point.

Laboratory Use Only

Storage Instructions:

Spine separate and freeze GH, Analyse glucose in house.

External Laboratory:

Austin Pathology

External Laboratory details...