The ranges for determining results of a prostate-specific antigen test vary from one lab to another, so there is no specific scale, notes WebMD. A particular lab may have a different range for what it considers normal.
In addition, there is no a particular cutoff point between a normal and an abnormal prostate-specific antigen level, explains Mayo Clinic. The results report usually contains the ranges a particular lab uses. The doctor evaluates the test results based on a patient's health and other factors. PSA levels tend to increase with age, so some doctors prefer using age-specific ranges, which are still controversial, according to WebMD. Other doctors prefer using one range for all ages.