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Testosterone Free (Equilibrium Ultrafiltration) & Total (LC/MS-MS) Blood Test
Item # LC070038
Evaluates testosterone levels above and below the standard limits of detection and quantification
Testosterone Free (Equilibrium Ultrafiltration) & Total (LC/MS-MS) Blood Test
Item # LC070038
Evaluates testosterone levels above and below the standard limits of detection and quantification
Testosterone is a steroid hormone from the androgen group primarily secreted in the testes of males and the ovaries of females with small amounts also secreted by the adrenal glands. This testosterone test uses special methodology to help quantify very low (and very high) testosterone values.
This test measures total testosterone by liquid chromatography and tandem mass spectrometry (LC/MS-MS), and free testosterone by equilibrium ultrafiltration.
- Total Testosterone (LC/MS-MS)
Testosterone by liquid chromatography and tandem mass spectrometry (LC/MS-MS) provides accurate measurements at very low concentrations, quantifying results of 2.5 ng/dL or greater, and so is the suggested test option for those with very low testosterone levels. This test can also be used for measuring levels above 1,500 ng/dL, as it provides an assay measurement range up to 5,000 (and higher with dilution procedures) (https://www.cdc.gov/clinical-standardization-programs/media/pdfs/2024/04/CDC-Certified-Testosterone-Assays-508.pdf)
- Free Testosterone by Equilibrium Ultrafiltration
Free testosterone is estimated in this profile by an indirect methodology called equilibrium ultrafiltration.
“Labeled” testosterone is added to the sample and allowed to come to equilibrium with testosterone in the serum at physiological temperature. Once equilibrium is achieved, the free testosterone is separated from the bound by filtration through a membrane by centrifugal ultrafiltration. The “labeled” portion of the protein-free ultrafiltrate is measured and used to calculate the percent free testosterone. The concentration of free testosterone in the original sample is then calculated by multiplying the percent free testosterone by the total testosterone concentration.
Instructions
Fasting is not required for this test. Take all medications as prescribed. If you are supplementing with any hormones, we suggest taking them approximately 2 hours prior to having your blood drawn to see peak levels. Hormones are best drawn between 8-10 AM.
NOTE
Results from this testosterone assay should not be directly compared to those obtained via standard immunoassay-based testosterone tests. This test is intended for use as a follow-up test when valid results cannot be quantified via other test methods or when specifically recommended by a healthcare professional.
This test’s turnaround time is typically longer than that of standard testosterone testing. Please allow 7-10 business days to receive results. Life Extension typically suggests direct immunoassay-based testing (included in all our hormone panels) for most people to obtain reliable free and total testosterone measurements with faster turnaround time. The regular free & total testosterone immunoassay is also available as a standalone test here: LC140103
The laboratory services are for informational purposes only. It is not the intention of National Diagnostics, Inc and Life Extension to provide specific medical advice but rather to provide users with information to better understand their health. Specific medical advice including diagnosis and treatment will not be provided. Always seek the advice of a trained health professional for medical advice, diagnosis or treatment.
Both the physician and the testing laboratory are independent contractors with whom National Diagnostics, Inc makes arrangements for your blood tests. Neither National Diagnostics, Inc or Life Extension will be liable for any acts or omissions of the physician, the testing laboratory, or their agents or employees.
A clinician's order is required for many tests. Where applicable, an independent clinician will review your test request and determine whether to authorize the test, if appropriate. For additional information, see PWNHealth Terms of Service.
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