Effect of Heamolysis on Prostate-Specific Antigen

Purpose. We have investigated the effect of haemolysis on free and total prostate-specific antigen (PSA) in daily clinical practice. Materials and Methods. Thirty-nine consecutive men were enrolled in this study. With an 18 gauge (G) needle 4？cc of blood samples were drawn from the right arm and 2？cc of it was expelled gently in a Vacutainer for regular PSA assay and the remaining was emptied into a second tube for complete haemolysis. Simultaneously 2？cc of more blood were taken with a 26？G insulin needle from the left arm of the same patient and expelled into another Vacutainer with forcing. All three samples were assayed for free PSA (fPSA), total PSA (tPSA), and potassium (K). Results. The results of the first tube were fPSA 0,535？ng/mL; tPSA 2,493？ng/mL; K+ 4,178？mmol/L. The results from the haemolysis tube were 0,170？ng/mL; 0,929？ng/mL; 39,545？mmol/L for fPSA, tPSA, K+, respectively, ( value was 0,001 for all the changes). In the same order the third tube results were 0,518？ng/mL, 2,322？ng/mL, and 7,11？mmol/L. Conclusions. Haemolysis may result in interference by decreasing free and total PSA falsely in daily blood draw practice, that could lead to misinterpreting the case in which especially small amount of increase may be of value. 1. Introduction Discrimination between benign and malignant conditions of the prostate has been made mainly by using digital rectal examination and PSA elevation, and a suspected malignancy has been confirmed by biopsy of the prostate due to poor specific and sensitive properties of PSA. PSA and its derivatives, although having some limitations, have been extensively used in prostate cancer detection, staging, and followup of the patients after treatment [1, 2]. While it has also been a subject of an extensive debate in diagnosis and screening the prostate cancer, followup of the patients was achieved with less debate by use of PSA and its derivatives [3–5]. Management of cases may be apparent provided that PSA levels are markedly over or below the cutoff value, but the state that PSA values are around the cutoff value has been a challenge for urologists [6, 7]. In such conditions little changes of PSA or its derivatives, produced by hidden factors related to either biological variation of PSA or laboratory analysis, may have inevitable effect on selecting patients for prostate biopsy [8, 9]. Herein, we present a study about probable effects of blood draw method on free and total PSA to investigate if blood collection method is of value in clinical practice. 2. Materials and Methods After local ethics committee