Zinc in post prostatic massage (VB3) urine samples: a marker of prostatic secretory function and indicator of bacterial infection.

The value of biochemical examination of post-prostatic massage (VB3) urine samples has been investigated. Measurement of zinc levels provides a good marker of prostatic secretory function. In the absence of prostatic carcinoma findings of greater or equal to 100 micrograms zinc in VB3 urines is strong evidence (2% false negatives) of an absence of infectious or inflammatory prostatic disease. Less than 40 micrograms of zinc is suggestive (14% false positives) of prostatitis. There is little need to consider the endogenous urinary zinc levels. This simple test should be of particular value in cases where an expressed prostatic secretion is not obtained (about 40% of this series of patients), when it would be a valuable adjunct to cytological and bacteriological examination of split urine samples.