Ejaculation can cause your PSA to rise briefly. So you should abstain from sexual activity for at least 48 hours before having your PSA level tested.
Blood for your PSA test probably will be taken from your arm. Wear a shirt or sweater with sleeves that roll up easily.
If you recently have had cystoscopy or needle biopsy of the prostate, let your doctor know so you can schedule your PSA test at another time. Those exams can raise PSA levels for a few weeks. This may make it harder to interpret the result of your PSA test.
PSA testing also should not be done until several weeks after you have been treated for a urinary tract infection.