effect of ejaculation on serum prostate specific antigen level in screening and non-screening population

background: the serum prostate specific antigen (psa) levels are used for prostate cancer screening. some conditions such as prostatitis, manipulation, and prostate cancer could influence on serum psa. the impact of ejaculation on serum psa is controversial. the aim of our study was to evaluate the relation of ejaculation and the levels of serum psa. materials and methods: in this cross-sectional study, 60 healthy voluntary men below and over 50 years during the year 2009-2011 were participated. after history taking, physical examination, and identical lower urinary tract symptoms score (american urologic association score = aua); three blood samples were taken before, 1 and 24 h after ejaculation. results: patients categorized into a non-screening group (age less than 50 years, n = 25), and screening group (age ≥ 50 years, n = 35). our data showed significant psa rising in both groups 1 h after ejaculation ( p value < 0.05); however, comparison of psa levels in both groups, before and 24 h after ejaculation showed no significant differences. spearman coefficient of correlation was showed a positive correlation between psa in all stage and aua score in the second group, but there were no such correlation in the first group. conclusion: there was a significant relationship between ejaculation and the levels of serum psa in screening and non-screening patients. however, in non-screening men significant rising of psa after 1 h of ejaculation was not important clinically (not achieve to greater than 4 ng/ml). taking a history of ejaculation in men older 50 years especially with high aua score could prevent false positive results and subsequent un-necessary work-ups.