26364 Insulin-like Growth Factor 1 (IGF-1), Pediatric With Z Score (503660)

​IGF-1 with Z Score

IGF-1 Pediatric with Z Score

​ZIGF-1 test code is ONLY for pediatric patients. All other patients should be ordered using in-house test code IGF1.

​IGF-1 measurements can be useful when evaluating patients of gestational age1 who are suspected of being (1) growth hormone-deficient2 or (2) acromegalic.

​Serum must be separated from cells within 45 minutes of venipuncture. Send serum in a plastic transport tube. Transfer specimen to a plastic transport tube before freezing. To avoid delays in turnaround time when requesting multiple tests on frozen specimens, please submit separate frozen specimens for each test requested.  ZIGF-1 test code is ONLY for pediatric patients. All other patients should be ordered using in-house test code IGF1.

Specimen not serum

​Plasma specimens may produce falsely elevated or decreased results. The IGF-1 reference intervals by pubertal Tanner stages reflect ranges and means based on asymmetric curves. Z scores are calculated based on the asymmetric curves with transformed data. Patient gender and date of birth must be provided in order to calculate a z score. Z scores will not be calculated for patients younger than three years or older than 18 years.

​Insulin-like growth factor 1 (IGF-1) is a polypeptide hormone that can affect growth-promoting activity and glucose metabolism. IGF-1 exists in a three-subunit complex form, with IGF-1 or IGF-2 (υ-subunit), IGFBP-3 (β-subunit), and acid labile subunit (ALS) (α-subunit). Samples are acid:ethanol extracted to remove IGF-1 from the complex, resulting in a consistent IGF-1 measurement, even with variable binding protein levels. The extracted sample is then analyzed by radioimmunoassay using a highly specific antibody.

An interpretive report will be provided