This ultrasensitive estradiol test is recommended for men. The commonly used estradiol test may overestimate estradiol in men. That test uses immunoassay technology that cannot differentiate C-Reactive Protein (involved in inflammation) from estradiol, so it reads the combination of the two as estradiol. This ultrasensitive estradiol test is based on liquid chromatography/mass spectrometry (LC/MS), an assay technology that does not have that limitation. 

Important note:  The blood sample is sent out to Quest Diagnostics Nichols Institute San Juan Capistrano, Caifornia.  Overnight delivery and testing is performed on Sunday and Friday.  Reports are available within 5-7 business days from the time the specimen is collected.

A single fasting growth hormone (GH) level is of limited value. The secretion of GH is episodic and pulsatile. GH has a half-life of 20 to 25 minutes. Testing for growth hormone deficiency or excess is best done as part of a dynamic test involving specific stimuli (see the online Endocrine Appendices: Growth Hormone Stimulation and Growth Hormone Suppression). Insulin-like growth factor-1 can also be useful in assessing growth hormone status.

Insulin-like Growth Factor 1, also known as IGF-1, is used as a biomarker for blood levels of human growth hormone. It is a hormone produced by the liver and other tissues which affects growth-promoting activities and glucose metabolism. The blood level of IGF-1 appears to fluctuate over 24 hours and is found to be related to growth hormone secretion.