Synonym/Acronym
N/A
Rationale
To evaluate testosterone to assist in identification of disorders related to early puberty, late puberty, and infertility while assessing gonadal and adrenal function.
Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.
Normal Findings
Method: HPLC/tandem MS for total testosterone and equilibrium dialysis for free testosterone.
Total Testosterone
| Age | Conventional Units | SI Units (Conventional Units × 0.0347) |
|---|---|---|
| 14–15 yr | ||
| Male | 33–585 ng/dL | 1.14–20.29 nmol/L |
| Female | Less than 75 ng/dL | Less than 2.6 nmol/L |
| 16–17 yr | ||
| Male | 185-886 ng/dL | 6.42–30.74 nmol/L |
| Female | Less than 20–75 ng/dL | Less than 0.69–2.6 nmol/L |
| 18–39 yr | ||
| Male | 300–1,080 ng/dL | 10.41–37.48 nmol/L |
| Female | 8–60 ng/dL | 0.28–2.08 nmol/L |
| Adult | ||
| Male | 300–890 ng/dL | 10.41–30.88 nmol/L |
| Female | 10–60 ng/dL | 0.35–2.08 nmol/L |
| Older adult | ||
| Male | 300–720 ng/dL | 10.41–24.98 |
| Female | 5–32 ng/dL | 0.17–1.11 |
Postmenopausal levels are about half the normal adult level for females; levels in women who are pregnant are three to four times the normal adult level for females who are not pregnant.
Free Testosterone
| Age | Conventional Units | SI Units (Conventional Units × 3.47) |
|---|---|---|
| 14–15 yr | ||
| Male | 4–140 pg/mL | 13.88–486 pmol/L |
| Female | Less than 10 pg/mL | Less than 34.7 pmol/L |
| 16–17 yr | ||
| Male | 38–173 pg/mL | 132–600 pmol/L |
| Female | Less than 10 pg/mL | Less than 34.7 pmol/L |
| Adult | ||
| Male | 50–244 pg/mL | 173.5–846.68 pmol/L |
| Female | Less than 10 pg/mL | Less than 34.7 pmol/L |
| Postmenopausal | Less than 10 pg/mL | Less than 34.7 pmol/L |
| Older adult | ||
| Male | 5–75 pg/mL | 17.35–260.25 pmol/L |
| Female | Less than 10 pg/mL | Less than 34.7 pmol/L |
(Study type: Blood collected in a red-, red/gray-, or green-top [heparin] tube; related body system: .)
Testosterone is the major androgen responsible for sexual differentiation. In males, testosterone is made by the Leydig cells in the testicles and is responsible for spermatogenesis and the development of secondary sex characteristics. In females, the ovary and adrenal gland secrete small amounts of this hormone; however, most of the testosterone in females comes from the metabolism of androstenedione. Testosterone levels have a slight diurnal variation with the highest levels occurring around 0800 and lowest levels around 2000.
Measurements of total testosterone levels are used most often in evaluating suspected hormone imbalances. Free testosterone is the active form of the hormone. It is used in conjunction with total testosterone to evaluate hormone levels in conditions known to alter the effectiveness of testosterone-binding protein, also called sex hormone–binding globulin (SHBG). Alterations in the affinity of SHBG to bind free testosterone are known to occur with obesity, liver disease, and hyperthyroidism. In males, a testicular, adrenal, or pituitary tumor can cause an overabundance of testosterone, triggering precocious puberty. In females, adrenal tumors, hyperplasia, and medications can cause an overabundance of this hormone, resulting in masculinization or hirsutism.
Increased In
Decreased In
Before the Study: Planning and Implementation
Teaching the Patient What to Expect
After the Study: Implementation & Evaluation Potential Nursing Actions
Treatment Considerations
Clinical Judgement
Follow-Up Evaluation and Desired Outcomes