Insulin-Like Growth Factor 1 (IGF-1) with Calculated Z-Score

Casandra

Casandra Test Code AR63355Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 2007698CPT Code 84305

Insulin-Like Growth Factor 1 (IGF-1) with Calculated Z-Score

Also known as: IGF-1Z

Clinical Use

Order Test

Use

The test aids in the diagnosis of growth hormone excess or deficiency disorders, such as Acromegaly and Growth Hormone Deficiency. It measures the level of IGF-1 which is an indicator of growth hormone activity in the body. A calculated Z-Score helps in assessing the age- and sex-adjusted IGF-1 level by comparing it to the population mean. This evaluation is crucial for managing and diagnosing conditions associated with abnormal growth hormone levels.

Special Instructions

Both patient age and sex are required for the Z-score calculation. It's important that samples are transported frozen to ensure stability, except for samples exposed to ambient temperatures for up to 24 hours or refrigerated for up to a week. Reference intervals are not established for individuals above 85 years old.

Limitations

Plasma, tissue, or urine specimens are unsuitable for this test, as are grossly hemolyzed or lipemic specimens. The test does not establish IGF-1 reference intervals for individuals older than 85 years, which may limit its applicability in diagnosing growth hormone disorders in this age bracket. Z-scores outside the -2.0 to 2.0 range may require further clinical correlation and investigation to understand the root cause, as these scores are indicative and not definitive diagnostics.

Test Details

New York Approved