Prostate specific antigen is produced in small amounts by cells in the prostate. This antigen, known as PSA, is often monitored by urologists to screen for clues concerning prostate health.
PSA levels are counted by nanograms of antigen per milliliter of blood, which is abbreviated as ng/ml. A nanogram is one-billionth of a gram, and a milliliter is one-one thousandth of a liter.
The normal range of PSA will vary from doctor to doctor, lab to lab and person to person. Generally speaking, 1 to 4 ng/ml is considered a normal range.
Most men will experience higher PSA levels as they age due to an enlarging prostate. Your doctor will likely take your age into consideration when reading your PSA levels.
High PSA counts usually indicate an enlarged prostate, as can occur with prostatitis or benign prostate hypertrophy (BPH). Only 25 percent of men with high PSA counts will be diagnosed with prostate cancer.
Though a low PSA count is preferred, false lows are possible. If you are obese or if you take specific medications that depress PSA production, your PSA levels may not read properly.
Though an elevated PSA count does not always mean cancer, 75 percent of those diagnosed with prostate cancer will have elevated PSA counts.