+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Evaluation of an immunoassay kit to measure free testosterone

Evaluation of an immunoassay kit to measure free testosterone

Actas Urologicas Espanolas 30(6): 598-601

The best indicators to the diagnosis of hypogonadism are free and bioavailable testosterone circulating levels. Free and bioavailable testosterone measurements are complex. However, simple kits for direct measurement of free testosterone by analog immunoassay are available. We examined the utility of an enzymoimmunoassay kit for free testosterone measurement. One hundred thirty-three healthy males were included. Total testosterone, SHBG, albumin and free testosterone was measured. We used two different methods to free testosterone estimation: direct measurement by enzymoimmunoassay and mathematical calculation with Vermeulen's formula, which uses albumin concentration, total testosterone and SHBG to calculate free testosterone (method recommended by the International Society for the Study of the Aging Male). We compared the two methods means values and a linear regression study was performed. Mean age was 37 +/- 11 years. Mean serum concentration for total testosterone was 21.43 +/- 6.8 nm ol/L. The mean value for free testosterone measured by direct and mathematical method was 0.0508 +/- 0.0118 nmol/L and 0.474 +/- 0.123 nmol/L respectively. In linear regression study exists a positive correlation between both methods (p< 0.05), although correlation coefficient is very low (r = 0.25). There are significant statistical differences between the measurements of free testosterone by direct and mathematical methods. Although certain correlation is observed, this is very low. In conclusion, free testosterone measurement by enzymoimmunoassay is not reliable.

Please choose payment method:

(PDF emailed within 1 workday: $29.90)

Accession: 048994443

Download citation: RISBibTeXText

PMID: 16921837

Related references

Development and clinical evaluation of ACS free PSA, an automated immunoassay to measure free PSA in serum. Clinical Chemistry 43(6 Part 2): S231, 1997

Analytical and clinical evaluation of ACS free PSA, an automated immunoassay to measure free PSA in serum. Tumor Biology 18(Suppl. 1): 3, 1997

Evaluation of assays available to measure free testosterone. Metabolism Clinical & Experimental 51(5): 554-559, 2002

Is it necessary to measure free testosterone to assess hyperandrogenemia in women? The role of calculated free and bioavailable testosterone. Experimental and Clinical Endocrinology and Diabetes 114(4): 182-187, 2006

Salivary testosterone: a good measure to reflect free testosterone. Archives of Internal Medicine 147(6): 1189, 1987

Evaluation of hirsutism by radio immunoassay of testosterone di hydro testosterone and estrone in saliva. Acta Endocrinologica Suppl. 103(256): 145, 1983

Free and total testosterone in the evaluation of prostate cancer Does low free testosterone predispose to more aggressive disease?. Journal of Urology 161(4 Suppl. ): 321, 1999

Testosterone, free testosterone, non-sex hormone-binding globulin-bound testosterone, and free androgen index: which testosterone measurement is most relevant to reproductive and sexual function in men with epilepsy?. Archives of Neurology 49(2): 133-135, 1992

Synthesis of new steroid haptens for radio immunoassay part 5 19 o carboxymethyl ether derivatives of testosterone a highly specific anti serum for immunoassay of testosterone from both male and female plasma without chromatography. Journal of Steroid Biochemistry 9(6): 539-546, 1978

Evaluation of an automated chemiluminiscence immunoassay for urinary free cortisol Comparison with Fluorescence polarization immunoassay. Clinical Chemistry 47(S6): A10-A11, 2001

Amerlex free thyroxine radio immunoassay a new investigative principle description evaluation and comparison with the dow lepetit free thyroxine radio immunoassay test. Nuclear Medizin 21(2): 72-78, 1982

Non-isotopic, two-step free thyroxine immunoassay: a better measure of free thyroxine than analogue radioimmunoassay. Annals of Clinical Biochemistry 27: 581-591, 1990

Micro encapsulation of antibody for use in a radio immunoassay for unbound free testosterone. Clinical Chemistry 26(7): 1036, 1980

The determination of total testosterone and free testosterone (RIA) are not applicable to the evaluation of gonadal function in HIV-infected males. Journal of Sexual Medicine 7(8): 2873-2883, 2010

Performance of total testosterone measurement to predict free testosterone for the biochemical evaluation of male hypogonadism. Journal of Urology 187(4): 1369-1373, 2012