Growth Hormone Binding Protein

Test Code

18407

CPT Codes
83520<br>Restricted Client Code

Preferred Specimen

0.3 mL serum

Minimum Volume

0.1 mL

Instructions

Allow a minimum clotting time of 30 to 60 minutes with serum separation within 2 hours of collection. Send serum in a plastic transport tube.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 7 days
Refrigerated: 14 days
Frozen: 14 days

Methodology
Enzyme-Linked Immunosorbent Assay (ELISA)

FDA Status
This test was performed using a kit that has not been cleared or approved by the FDA. The analytical performance characteristics of this test have been determined by Esoterix. This test should not be used for diagnosis without confirmation by other medically established means.

Setup Schedule

Set up: Varies; Report available: 8-11 days

Reference Range

11-26 ng/mL

Clinical Significance

Reduced or absent GHBP is found in GH insensitivity due to inactivating receptor binding mutations as typified by Laron dwarfism. The most clinically relevant use of GHBP measurements is to confirm suspected Laron dwarf GH insensitivity due to genetic GH receptor defect. Other forms of GH receptor insensitivity, however may have normal or high GHBP levels. The levels of GHBP may be explained by the underlying mechanism for insensitivity, accordingly, inability to dimerize, errors in the trans-membrane structure, or in downstream actions may have high or normal GHBP levels.

Studies show that GHBP levels decrease in acromegaly, with normalization on successful treatment. The converse is not true ? high GHBP levels are not found associated with GH deficiency.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.