Interpretive Data:

The assay is standardized to the 2nd WHO International Std, 98/574: Somatotropin (22 kDa). Due to significant overlap of GH levels in normal and diseased populations, random, single GH levels are often inadequate. In order to evaluate growth hormone deficiency (GHD) or excess, the stimulation or suppression tests are necessary. In the evaluation of a child with clinical criteria for GHD, per 2000 Consensus Guidelines, a peak GH concentration <10 ng/mL has traditionally been used to support diagnosis. (1) However, at the time of publication of these guidelines, the IS available was 88/624. For this reason, and due to the advent of more sensitive assays that use monoclonal antibodies, some experts recommend a more stringent cut-off of 7µg/L for the diagnosis of GHD. (2) For suppression testing, in evaluation of acromegaly, normal subjects have a nadir growth hormone (GH) concentration of <0.3 ng/mL after ingestion of a 75-gram glucose dose. Using the Access GH assay, a cutoff of 0.53 ng/mL for nadir GH was found to most accurately differentiate patients with acromegaly in remission from active disease with a sensitivity of 97% (95% CI, 83%-100%) and a specificity of 100% (95% CI, 82%-100%).(3) References:

Growth Hormone Research S. Consensus guidelines for the diagnosis and treatment of growth hormone (GH) deficiency in childhood and adolescence: summary statement of the GH Research Society. GH Research Society. The Journal of clinical endocrinology and metabolism 2000;85:3990-3.

Murray PG and Clayton PE. Disorders of Growth Hormone in Childhood. www.ednotext.org (Updated: November 16, 2016).

Bancos I, Algeciras-Schimnich A, Woodmansee WW, et al. Determination of nadir growth hormone concentration cutoff following oral glucose tolerance testing using the Beckman Coulter ultrasensitive growth hormone assay patients with newly diagnosed acromegaly, acromegaly in remission, and healthy subjects. Endocr Pract 2013;19:937-45.