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Test Code Billings Clinic: 4064 Testosterone, Total Only, Serum or Plasma

Important Note

A strong interaction with Nandrolone decanoate, 11β-hydroxytestosterone, and 11-ketotestosterone was found. Do not use samples from patients receiving these compounds.

Specimens that contain biotin at a concentration of 30 ng/mL demonstrate less than or equal to 10% change in results. Biotin concentration greater than this may lead to falsely elevated results for patient samples.

Performing Laboratory

Billings Clinic Laboratory: Chemistry

Useful For

  • Evaluation of men with symptoms or signs of possible hypogonadism, such as loss of libido, erectile dysfunction, gynecomastia, osteoporosis, or infertility
  • Evaluation of boys with delayed or precocious puberty

  • Monitoring testosterone replacement therapy

  • Monitoring antiandrogen therapy (eg, used in prostate cancer, precocious puberty, treatment of idiopathic hirsutism, male-to-female transgender disorders, etc.

  • Evaluation of women with hirsutism, virilization, and oligoamenorrhea

  • Evaluation of women with symptoms or signs of possible testosterone deficiency

  • Evaluation of infants with ambiguous genitalia or virilization

  • Diagnosis of androgen-secreting tumors

Methodology

Direct Chemiluminescent Immunoassay

Specimen Requirements

Submit only 1 of the following specimens:

Serum or plasma should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.

 

Plasma

  • Draw blood in a green-top (lithium heparin) tube(s).
  • Keep tube capped at all times
  • Spin down and send 1.0 mL of heparinized plasma frozen.

 

Serum

  • Draw blood in a plain, red-top tube(s) or a serum gel tube(s).
  • Keep tube capped at all times
  • Spin down and send 1.0 mL of serum frozen

Storage/Stability

Specimen Type Temperature Time
Serum, Plasma Refrigerated 7 days
  Frozen (preferred) 1 month
  Ambient 2 days

 

Reject Due To

  • Specimens that have been stored at room temperature > 48 hours
  • Specimens frozen and thawed more than 3 times
  • Gross hemolysis
  • Gross icterus

Reference Values

Males:

2-11 years: 7-11 ng/dL

11-12 years: 7-479 ng/dL

12-13 years: 7-488 ng/dL

13-14 years: 8-550 ng/dL

14-15 years: 9-535 ng/dL

15-16 years: 66-757 ng/dL

16-21 years: 228-711 ng/dL

21-50 years: 197-670 ng/dL

50-89 years: 188-685 ng/dL

 

Females:

2-11 years: 7-12 ng/dL

11-16 years: 7-28 ng/dL

16-21 years: 12-43 ng/dL

21-50 years: 8-35 ng/dL

50-89 years: 7-36 ng/dL

 

Tanner Stages Males:

I (prepubertal): <7-13 ng/dL

II: <7-79 ng/dL

III: <7-499 ng/dL

IV: 79-747 ng/dL

V (young adult): 225-670 ng/dL

 

Tanner Stages Females:

I (prepubertal): <7-10 ng/dL

II: <7-30 ng/dL

III: <7-30 ng/dL 

IV: <7-35 ng/dL

V (young adult): 12-39 ng/dL

Day(s) Test Set Up

Daily

Test Classification and CPT Coding

84403 - Testosterone

LOINC Code Information

Reporting Name LOINC Code
Testosterone 2986-8

 

Interferences

  • Samples with conjugated bilirubin concentrations > 15 mg/dL will cause erroneous results.
  • Samples with unconjugated bilirubin concentrations > 20 mg/dL will cause erroneous results.
  • A strong interaction with Nandrolone decanoate, 11β-hydroxytestosterone, and 11-ketotestosterone was found. Do not use samples from patients receiving these compounds.