Clinical Significance:
Testosterone is a potent androgen produced primarily by metabolism of Androstenedione and Androstenediol.  It is converted to Estradiol, Dihydrotestosterone, Androsterone, and Etiocholanolone.  It is excreted into the urine as conjugated and unconjugated (Free) forms of Testosterone and also is responsible for much of the 17-Ketosteroids found in the urine.  Testosterone is strongly bound to Testosterone Binding Protein, weakly bound to Albumin and also present in the bioactive unbound (Free) form.  In males the vast majority of Testosterone is produced by the Leydig cells under the control of Luteinizing Hormone.  In females, most of the Testosterone is of adrenal origin.  Testosterone is responsible for development of secondary sex characteristics including external genitalia, growth of facial hair and pubic hair.  Increased levels are found in patients with Polycystic Ovarian Disease, Hirsutism, Ovarian Tumors, Arrhenoblastomas, Hilus Cell Tumors, Adrenal Hyperplasia and Adrenal Tumors.  Decreased levels are found in Hypogonadism, Klinefelter’s Syndrome, Hypopituitarism, and Estrogen Therapy.

Reference Ranges:
Male:                          450 – 1000 ng/dl
Female:                      20 –      54 ng/dl

Testosterone is measured by EIA/ELISA following extraction of specimens. 

Patient Preparation:
Patient should not be on any Steroid, Thyroid, ACTH, Estrogen or Gonadotropin medications, if possible, for at least 48 hours prior to collection of specimen.

Specimen Collection:
3 ml serum or EDTA plasma should be collected and separated as soon as possible.  Minimum specimen size is 1 ml.

Special Specimens:
For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.) contact the Institute for requirements and special handling.

Shipping Instructions:
Ship specimens at room temperature or frozen in dry ice.

1. S Loric, J Guechot, F Duron, P Aubert, and J Giboudeau.  Determination of Testosterone in Serum Not Bound by Sex-Hormone-Binding Globulin:  Diagnostic Value in Hirsute Women.  Clinical Chemistry 34: 1826-1829, 1988.

2. TJ Wilke and David J Utley.  Total Testosterone, Free-Androgen Index, Calculated Free Testosterone, and Free Testosterone by Analog RIA Compared in Hirsute Women and in Otherwise-Normal Women with Altered Binding of Sex-Hormone-Binding Globulin.  Clinical Chemistry 33: 1372-1375, 1987.