If the massage is too light, you can’t squeeze out most of the prostate fluid, so the cell count of the prostate fluid is relatively reduced. 4, chronic prostatitis when often focal changes: during rectal finger examination often found irregularities in the surface of the prostate, while can be palpable limited hard nodes and limited tender areas, so any one massage does not reflect the entire prostate. 5, with the anatomy of the prostate itself: the prostate is divided into two parts: the central zone and the peripheral zone, from the pathological statistics, the peripheral zone is more infected than the central zone, but the discharge of secretions from the peripheral zone is more difficult than the central zone, so the prostatic fluid obtained from prostate massage mainly comes from the central zone, rather than from the peripheral zone, which is more susceptible to infection, so the prostate massage fluid examination does not fully reflect the infection of the entire prostate. The prostate massage fluid examination cannot fully reflect the infection of the whole prostate. The smear thickness varies, with heaps of overlapping white blood cells seen in some fields and only a few in others, with an error of 20% to 25%.