Age-specific reference ranges of serum prostate-specific antigen in Iranian men

Prostate-Specific Antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KLK3), is the best marker for early diagnosis of prostate cancer. Since age and race are affecting PSA levels, determining age-specific reference ranges of PSA in every community is necessary for increasing the efficiency rate of PSA. The aim of the present study was to evaluate the normal distribution of total prostate-specific antigen (TPSA) and free prostate-specific antigen (FPSA) and determine age-specific reference ranges of PSA in Iranian men. In this cross-sectional study, 1200 normal men with the age range of 50 to 79 referred to Shahid Rajaie Hospital, Qazvin Province in Iran, from 2011 to 2013. After excluding patients with prostate cancer and urinary tract infection, 1020 men were included in this study. Then, their blood samples were collected and after the extraction of serum from blood, serum levels of FPSA and TPSA were measured using commercial kits; the reference range of PSA was specified for each age group and compared with reference ranges of other populations. The mean age of the patients was 61.03±7.5 years and the mean values of FPSA and TPSA were 0.47±0.6 ng/ml and 1.56±2.05 ng/ml, respectively. PSA serum levels (95th percentile range) in 50 to 59, 60 to 69 and 70 to 79-year age groups were 0-3.6 ng/ml, 0-5.7 ng/ml and 0-6.8 ng/ml, respectively. TPSA (r= 0.2, P< 0.001) and FPSA (r= 0.22, P< 0.001) were significantly associated with age. In addition, a significant relationship was found between TPSA serum levels and alcohol consumption (P= 0.017), smoking (P< 0.001) and family history of prostate cancer (P= 0.014). Findings of the present study showed that PSA levels are correlated with age. It was also revealed that the PSA age-specific reference range obtained in this study is different from other races and is specific to Iranian men. Therefore, age-specific reference ranges of PSA obtained in the present study can increase PSA test sensitivity and specificity by reducing unnecessary diagnostic procedures and early detection of prostate cancer in Iranian men.