Test Overview
Test Methodology

Chemiluminescent Immunoassay (CLIA)

Test Usage

A reliable indicator of LH secretion and Leydig cell function. Evaluation of gonadal and adrenal function. Helpful in the diagnosis of hypogonadism in males and hirsutism and virilization in females.

Reference Range *

Male 1-10 yrs: 0.00-0.20 ng/mL; Male 10-14 yrs: 0.10-5.00 ng/mL; Male 14-18 yrs: 1.00-9.50 ng/mL; Adult Male: 2.50 - 9.50 ng/mL; Female 1-10 yrs: 0.00-0.20 ng/mL; Female 10-14 yrs: 0.10-0.50 ng/mL; Adult Female: 0.10 to 0.90 ng/mL. Note that there can be significant diurnal variation in testosterone levels in both males and females. Reference ranges are based on morning samples. Caution should be taken in interpreting values drawn at other times of the day.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Less than 2% cross reactivity with dihydrotestosterone. Total serum testosterone may be normal in women with hirsutism, who may have abnormal free testosterone index. This assay also measures dihydrotestosterone which is normally less than 20% of the testosterone concentration. Cyproterone, diethylstilbestrol, and metyrosone decrease testosterone values. Clomiphene, cimetidine, estrogens, and oral contraceptives increase testosterone levels. Testosterone levels are highest in morning. Male levels drop 30-50% and female levels drop 20% by midafternoon.

Test Details
Days Set Up
Daily, 24 hours
Analytic Time

4 hours

Soft Order Code
TESTO
MiChart Code
Testosterone
Synonyms
  • TESTO
  • TESTOSTERONE
  • TESTOSTERONE LEVEL
Laboratory
Chemical Pathology
Section
Automation
Specimen Requirements
Collection Instructions

Collect specimen in an SST (preferred) or red top tube. Centrifuge, aliquot serum into a plastic vial and refrigerate up to 48 hours or freeze for longer storage.

Alternate Specimen
Red Top Tube
Yellow Top Tube
Red Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.25 mL serum
Additional Information

In males, testosterone is normal or decreased in hypopituitarism, Kallmann's syndrome, isolated gonadotrophin deficiency and Klinefelter's syndrome. It is normal in cryptorchidism, azoospermia and oligospermia. It is decreased in delayed puberty, primary testicular failure and anorchia. Testosterone is normal or increased in complete testicular feminization syndrome. Testosterone is increased in precocious puberty, related to idiopathic or CNS lesion, or to adrenal tumors or congenital adrenal hyperplasia. Testosterone exists in serum both free and bound to albumin and to sex hormone binding globulin. The latter is increased by estrogen and thyroid hormone and is decreased by androgen excess. In females, testosterone provides useful information in evaluating hirsutism and virilization. Many hirsute women exhibit normal testosterone levels in peripheral circulation. It is therefore highly recommended that binding index (free testosterone) be determined in cases of suspected androgen excess. Determination of testosterone and androstenedione in adrenal and vein plasma may be helpful in locating the site of excess androgen production. In males, it is useful in evaluating impotence, hypogonadism, delayed and precocious puberty. In general, there appears to be little advantage in doing urine testosterone measurements compared to (or in addition to) serum measurements and the serum test is recommended.

Billing
CPT Code
84403
Fee Code
23348
LOINC
2986-8
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