Definition

A laboratory test that measures the amount of genetic material called PCA3 mRNA and PSA mRNA in the first urine sample after a digital rectal examination. PCA3 mRNA and PSA mRNA are made by normal prostate cells and prostate cancer cells but are made in higher amounts by prostate cancer cells. The PCA3 score is based on the ratio of PCA3 mRNA to PSA mRNA in the urine. A high PCA3 score may be a sign of prostate cancer. The prostate cancer antigen 3 mRNA test may be done in men with a high PSA level whose biopsy of the prostate did not show cancer. The prostate cancer antigen 3 mRNA test is used to help decide if another prostate biopsy may be needed. Also called PCA3 mRNA test.