Any assay is designed to measure something within certain concentration limits. Many of the articles examine populations with very low PSA levels. But where prostate cancer is just a suspicion a serum PSA might well be part of the diagnostic regimen in a man who is sexually active. Knowing whether and how ejaculation affects serum PSA will be important. That will affect the interpretation and usefulness of the test.
Many articles look only at young men, and at times early after ejaculation.
Those that look at older men generally exclude those with prostatic disease. We found nine. The details are shown in the Table. In order to help sort wheat from chaff, we made a decision as to whether the studies were valid or not. Four studies were invalidated by these criteria.