Different stability of free and complexed prostate-specific antigen in serum in relation to specimen handling and storage conditions.
The effect of sample collection, storage conditions (time and temperature), and freeze-thaw cycles on the stability of free prostate-specific antigen (fPSA), PSA complexed with alpha1-antichymotrypsin (ACT-PSA), and total PSA (tPSA) in serum was studied. The analytes were quantified using immunoassays for tPSA and fPSA on the Elecsys system 2010 and a research assay for ACT-PSA on the ES system (Roche Diagnostics). The stability of the analytes was calculated as percentages of the values measured in samples 1 h after blood collection. When the samples were stored at 37 degrees C, at room temperature or at 4 degrees C, the stability of ACT-PSA was less impaired than that of fPSA. To avoid erroneous results in the determination of PSA isoforms and their corresponding ratios, serum samples should be preserved at 4 degrees C when the analysis is performed within 8 h after blood collection, or they should be stored at -80 degrees C if the analysis is not feasible during that period.
Jung
K
K
Department of Urology, University Hospital Charité, Humboldt University Berlin, Germany. klaus.jung@charite.de
Lein
M
M
Brux
B
B
Sinha
P
P
Schnorr
D
D
Loening
S A
SA
D001774:Blood Chemical Analysis / Q000379:methods*; D005615:Freezing; D006801:Humans; D007118:Immunoassay; D008297:Male; D017430:Prostate-Specific Antigen / Q000032:analysis / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood; D015203:Reproducibility of Results; D013048:Specimen Handling; D013696:Temperature; D013997:Time Factors; D000514:alpha 1-Antichymotrypsin / Q000097:blood
D000514:alpha 1-Antichymotrypsin; D017430:Prostate-Specific Antigen