PTU - Polskie Towarzystwo Urologiczne
list of articles:

The influence of external factors on PSA value
Article published in Urologia Polska 2008/61/Supl. 1.


Roman Sosnowski, Agata Wlazło, Tomasz Demkow, Iwona Skoneczna, Janina Kamińska, Maria Kowalska, Wojciech Michalski
Klinika Nowotorów Układu Moczowego, Centrum Onkologii w Warszawie
Zakład Markerów Nowotworowych, Centrum Onkologii w Warszawie
Biuro Badań Klinicznych i Biostatystyki, Centrum Onkologii w Warszawie



The prostate specific antigen (PSA) is an acknowledged marker in different conditions of the prostate amongst which is prostate cancer. The PSA value depends on the given ailment of the prostate gland. It is commonly known that the serum PSA concentration changes under the influence of different drugs, prostate conditions, urological surgical procedures or ejaculation. Until now it isn’t clear whether preanalytical external factors have an influence on the final PSA result, such as the time and temperature at which the samples are stored from the moment of blood collection.


The purpose of the present study was to establish the influence of preanalytical external factors (temperature and time of storage condition before analysis) on the total PSA (tPSA) serum value.

Materials and methods.

47 subsequent patients with prostate cancer were included and routine blood samples were collected. tPSA was identified using the Abbott set TotalPSA. Four measurement series of PSA levels were carried out in each patient putting them in appropriate groups: series 1 – measurement just after collecting blood sample; series 2 – measurement after 4 hour incubation period at 300C; series 3 – leaving sample at room temperature for 4 hours; series 4 – leaving sample at 40C for 24 hours.


tPSA median and range for the series 1 was: 0.656 (0.001- 152.1) [ng/ml]. The number of patients with tPSA above and below 1.000 ng/ml was 26 and 21, respectively. The percentage difference of PSA values between series 2, 3, 4 and series 1 were analyzed. The One-Sample T-test was used with H0: assuming zero difference. No statistical significant difference was found between the series. The minimal detectable difference, at the test power level of 0.9, for all tests, was less than 2.8%


tPSA is a stable protein, whose serum concentration doesn’t change under the influence of temperature or time in which the samples are stored. The character of prostate pathology but not the analyzed external factors have influence on the obtained changes in the tPSA values measured in the same patient.