Testosterone, Total

CPT: 84403

Expected Turnaround Time

24 Hours

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Specimen Requirements


Serum, Plasma


SST (Serum), Red Top (Separate Serum), Lithium Heparin (Plasma), EDTA (Plasma), Sodium Heparin (Plasma)

Storage Instructions

Room Temp., Refrigerated (2-8 C)

Stability Requirements

Room temp. 7 days, Refrigerated 7 days

Test Details

Additional Information

In men, testosterone is the primary sex hormone. It’s in charge of a man’s physical appearance. Although it is thought to be a “masculine” sex hormone, it is found in both men and women’s blood.  

Testosterone is primarily produced in the male testicles by unique endocrine tissue called Leydig cells. It’s also made by the adrenal glands in both males and females, as well as the ovaries in females in modest amounts. 

In males, testosterone promotes the formation of secondary sex characteristics such as penis size, body hair growth, muscle development, and a deeper voice. It is abundant in males during adolescence and adulthood in order to regulate sex drive and preserve muscle mass. Estradiol is the major sex hormone in females, and testosterone is converted to it in women. 

The pituitary gland produces luteinizing hormone, which stimulates and regulates testosterone synthesis. Testosterone functions in a negative feedback loop: when testosterone levels rise, LH production falls, slowing testosterone production; lower testosterone levels cause higher LH production, which promotes testosterone production. 

Testosterone levels fluctuate throughout the day, increasing in the early morning hours and dropping in the evening. Levels rise after activity and fall as people get older. 

About two-thirds of testosterone is attached to sex-hormone binding globulin in the blood, with the remaining one-third bound to albumin. Only a small percentage of testosterone is released into the blood as free testosterone. The bioavailable fraction is the free plus albumin-bound testosterone, which can act on target tissues. 


  1. Grand, G, et al. (2022) The role of testosterone in spermatogenesis: Lessons from proteome profiling of human spermatozoa in testosterone deficiency. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5029560/ 
  2. Rothman MS, et al. (2011) Reexamination of testosterone, dihydrotestosterone, estradiol and estrone levels across the menstrual cycle and in postmenopausal women measured by liquid chromatography-tandem mass spectrometry. https://pubmed.ncbi.nlm.nih.gov/36282060/ 

Statement on Medical Necessity
All ordered tests should be medically necessary for the diagnosis or detection of disease, illness, impairment, symptom, syndrome, or disorder and the results should be used in the medical management and treatment decisions for the patient. Solaris requires ICD-10 codes with each order for lab testing and both the tests ordered and the diagnosis should be documented in the provider’s medical record for the patient. The United States Department of Health and Human Services, Office of Inspector General, takes the position that a provider who orders medically unnecessary tests may be subject to civil penalties.

Panels and Profiles
Solaris offers Providers the convenience of ordering test combinations in a group at times with the flexibility to choose appropriate test(s) for individual patients. Providers should only order those tests that he or she believes are medically necessary for each patient, and a lesser inclusive profile or individual tests should be ordered if not all tests in the test combination/profile are medically necessary. All tests offered in a test combination/profile may be ordered separately as individual tests. Solaris encourages clients to contact their Solaris representative if the testing configurations shown do not meet individual needs for any reason, or if some other combination of procedures is needed.

CPT Codes
CPT Codes listed are in accordance with Current Procedural Terminology, a publication of the American Medical Association. CPT codes are the responsibility of the billing party and are listed here for informational purposes. Correct coding may vary from one carrier to another. Solaris may bill specific carriers using codes other than what is shown.


For questions or inquiries related to testing please reach out to
customerservice@solarisdx.com or contact us by phone at (844) 550-0308.