A PSA test result between 4 and 10 indicates a 25 percent chance that prostate cancer exists, explains American Cancer Society. The chance of having prostate cancer when PSA levels rise above 10 increases to 50 percent, while levels below 4 drop to about 15 percent.
Historically, the medical community has accepted PSA levels below 4 as normal. Studies show that some men with PSA levels below 4 develop cancer, while some men with PSA levels above 10 do not develop cancer, reports National Cancer Institute. Other factors can cause a man's PSA level to rise. Inflammation of the prostate, the presence of a urinary tract infection or an enlargement of the prostate can all elevate PSA levels. Prostate surgery or prostate biopsies have a tendency to elevate levels as well.
If a healthy man without prostate cancer symptoms has an elevated PSA level, an additional PSA test is warranted. A patient with consistently elevated PSA tests should be monitored carefully, notes National Cancer Institute. A urine test can be used to rule out a urinary tract infection, and imaging tests, such as X-rays, transrectal ultrasound or cystoscopy, can be used to determine a diagnosis. Once prostate cancer is suspected, a prostate biopsy is performed.