Post-ejaculation urinalysis is a test done on the man’s urine after ejaculation. This test is usually done when the semen volume is low and because of retrograde ejaculation. In retrograde ejaculation, there is a backward flow of semen into the bladder rather than flowing out via the urethra. The semen gets mixed with the urine and is ejected as a waste. This occurs at the time of ejaculation. Retrograde ejaculation is a form of male infertility problem.