albumin - publications
Are there Variances of Calculated Free Testosterone Attributed to Variations in Albumin and Sex Hormonebinding Globulin Concentrations in Men?
Endocr Pract. 2013 Mar 29;:1-21
Authors: Guay AT, Traish AM, Hislop-Chestnut DT, Doros G, Gawoski JM
Objective: Calculated free testosterone (cFT) is determined from total testosterone (TT), sex hormone binding globulin (SHBG) and Albumin (Alb) using mathematical formulae. Variations in cFT due to changes in SHBG or Alb have not been investigated. We evaluated potential cFT variances determined with fixed Alb (4.3 g/dL) compared to measured Alb, and the point at which low SHBG and Alb combinations produced significant cFT variance.Method: We analyzed 11,176 data points in 5,797 men. cFT values with fixed versus actual Alb values were evaluated and contrasted. cFT levels were determined theoretically for all possible combinations of TT, SHBG and Alb, in 8,343,552 combinations. Agreement between the two measures was assessed with Lin's concordance coefficient. Statistical analyses were performed using R software version 2.12.1.Results: Mean Alb was 4.06 ± 0.32 g/dL. Mean SHBG was 39.0 ± 23.6 nmol/L. A fixed Alb of 4.3 g/dL produced no significant variance for most evaluations of cFT. The accuracy decreased with Alb ≤ 3.5 g/dL in combination with SHBG ≤ 30 nmol/L, and exists in 1.2% of the data points in men.Conclusion: A fixed Alb of 4.3 g/dL is acceptable for most clinical evaluations. If Alb is ≤ 3.5 g/dL, along with SHBG ≤ 30 nmol/L, the variance increases, then a free testosterone (FT) measurement by equilibrium dialysis is warranted for better accuracy.
PMID: 23543029 [PubMed - as supplied by publisher]