Testosterone, Free & Weakly Bound (Bioavailable)
Fasting Required: No

Specimen: Blood

Results: 7-10 Business days

Description:
Free and bioavailable testosterone testing is indicated when the total testosterone is near the lower limit of the adult male reference range, and diagnosis of hypogonadism is being considered in men and mild
hyperandrogenism is being considered in women. In boys of pubertal age, free and bioavailable testosterone levels may be a better indicator of hypogonadism than total testosterone levels. Low concentrations of the free and bioavailable forms may indicate delayed puberty.

Typically, free and bioavailable testosterone levels parallel the total testosterone level. However, this may not be the case when sex hormone-binding globulin (SHBG) concentration is affected by certain medical conditions or medicines, including: Liver disease and severe systemic illnesses, Inherited abnormalities in SHBG, Treatment with corticosteroids or sex steroids, eg, oral conjugated estrogen.
Women with polycystic ovarian syndrome (PCOS) may have insulin resistance that is associated with low levels of SHBG. In this circumstance, free and bioavailable testosterone may be elevated more than the total testosterone level.

Includes:
Total Testosterone, Free and Bioavailable Testosterone (calculated), Sex Hormone Binding Globulin, Albumin

Methodology:
Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS) • Calculation (CALC) • Spectrophotometry (SP) • Immunochemiluminescent Assay

Clinical Significance:
Helpful in assessing testicular function in males and managing hirsutism, virilization in females.

Note: Result turn around times are an estimate and are not guaranteed. Our reference lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.