Growth Hormone (GH)

Cleveland HeartLab G, Test

NEW YORK DOH APPROVED: YES
CPT Code: 83003
Order Code: C1409
ABN Requirement: No
Synonyms: Human Growth Hormone, hGH, HGH, GH
Specimen: Serum
Volume:  1.0 mL
Minimum Volume:  0.5 mL
Container: Gel-barrier tube (SST, Tiger Top)

Collection:

  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
  3. Allow blood to clot 30 minutes.
  4. Centrifuge at 1300 rcf for 10 minutes.

Patient Preparation:  Fasting 12-14 hours is recommended. Patient should be in a resting state for 30 minutes prior to collection.

Transport: Store serum at 2°C to 8°C after collection and ship the same day per packaging instructions provided with the Cleveland HeartLab, Inc. shipping box.

Stability:

Ambient (15-25°C): 7 days
Refrigerated (2-8°C): 14 days
Frozen (-20°C): 28 days
Deep Frozen (-70°C): 28 days

Causes for Rejection: Specimens other than serum; improper labeling; samples not stored properly; samples older than stability limits

Methodology: Immunoassay (IA)

Turn Around Time: 5 days

Reference Range:

Age ng/mL
Children (<20 years) ≤13.0
Adults (≥20 years) ≤10.0

Using the glucose tolerance (GH suppression) test, acromegaly is ruled out if the patient’s GH level is <4.0 ng/mL at any point in the timed sequence.

Using GH stimulation testing, the following results at any point in the timed sequence makes GH deficiency unlikely:

Adults (≥20 years)

Insulin Hypoglycemia       ≥5.1 ng/mL
Arginine/GHRH                ≥4.1 ng/mL

Children (<20 years)

All Stimulation Tests        ≥10.0 ng/mL

Intended Use: The growth hormone test is used to evaluate individuals with symptoms of growth hormone abnormalities, as a follow-up for other abnormal hormone results, or to evaluate pituitary function.

Limitations: Because of a pulsatile secretion pattern, random (unstimulated) Growth Hormone (GH) levels are frequently undetected in normal children and adults and are not reliable for diagnosing GH deficiency. Regarding suppression tests, failure to suppress GH is diagnostic of acromegaly.