Effect of terminal renal failure on the ratio of free to total prostate-specific antigen.
OBJECTIVE
To evaluate the effect of terminal renal failure on the ratio of free to total prostate-specific antigen (PSA).


METHODS
We measured free and total PSA in a group of 48 men on chronic hemodialysis. Samples were taken before dialysis and compared with a control group of 101 men without known prostatic or renal disease. Measurements of total and free PSA were made simultaneously with an ES-300 analyzer from Boehringer Mannheim according to the manufacturer's instructions.


RESULTS
Patients on hemodialysis have lower complexed PSA but higher free PSA than controls. Therefore, we observed a markedly higher calculated proportion of free PSA in the dialysis group (0.54 +/- 0.16 vs. 0.33 +/- 0.14, p < 0.00001). The calculated proportion of free PSA decreases progressively as the levels of total PSA increases from 0 to 4 microg/l in both groups. By multivariate analysis, total PSA (p < 0.00001) and dialysis (p < 0.00001) were independent predictors of the fraction of free PSA. Age had no significant effect after correction for total PSA (p = 0.23).


CONCLUSIONS
Patients on hemodialysis have normal total PSA but a significantly higher proportion of free PSA. Caution is therefore recommended for the interpretation of free PSA in that population since cutoff established in patients without renal disease may be inappropriate.
Douville
P
P
Centre Hospitalier Universitaire de Québec, Canada.
Tiberi
M
M
D001322:Autoanalysis; D003404:Creatinine / Q000097:blood; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011336:Probability; D017430:Prostate-Specific Antigen / Q000097:blood*; D012016:Reference Values; D006435:Renal Dialysis; D014508:Urea / Q000097:blood
D014508:Urea; D003404:Creatinine; D017430:Prostate-Specific Antigen