The PSA is used as a guide to estimate the risk of prostate cancer. The higher the PSA, the greater the chance of prostate cancer.
- PSA levels under 4 ng/mL: “normal”
- 4 to 10 ng/mL: 20 to 30% risk
- 10 to 20 ng/mL: 50 to 75% risk
- Above 20 ng/mL: 90%.
When prostate cancer develops, the PSA level usually goes above 4. Still, a level below 4 does not guarantee that a man doesn’t have cancer – about 15% of men with a PSA below 4 will have prostate cancer on biopsy. Men with a borderline PSA level between 4 and 10 have about a 1 in 4 chance of having prostate cancer. If the PSA is more than 10, the chance of having prostate cancer is more than 50%..