Age-specific reference ranges for prostate-specific antigen (PSA) in Jordanian patients. 
In this study, the normal distribution of total prostate-specific antigen (TPSA) and free prostate-specific antigen (FPSA) values and the appropriate reference ranges for prostate-specific antigen (PSA) in Jordanian patients were established; the values were then compared to those of other studies.  Serum TPSA and FPSA levels in 1852 men with no diagnostic prostate cancer, as well as in patients whose PSA value was obtained as part of the clinical work-up of symptoms relating to non-neoplastic urologic conditions, were estimated during the period 1993-2001: 1561 (84.3%) were above 40 y of age or older.  We studied the data as a function of age to determine the usefulness of measuring TPSA, FPSA, and their ratio as screening tests for prostate cancer risk patients.  Using the 95th percentile, the recommended age-specific reference ranges of TPSA and FPSA values were as follows: for the age group 30-34 y, 2.3 and 0.51 ng/ml, respectively; for the age group 35-39 y, 2.9 and 0.59 ng/ml, respectively; for the age group 40-44 y, 3.2 and 0.63 ng/ml, respectively; for the age group 45-49 y, 3.75 and 0.71 ng/ml, respectively; for the age group 50-54 y, 3.8 and 0.83 ng/ml, respectively; for the age group 55-59 y 3.75 and 0.96 ng/ml, respectively; for the age group >60 y old, 4.3 and 1.26 ng/ml, respectively.  There was a continuous increase in TPSA and FPSA means and medians throughout the study period with a significant correlation (P<0.001, P<0.05) for TPSA and FPSA levels), respectively, and advancing age group.  With regard to the ratios of FPSA-to-TPSA for each age group we found no correlation between them.  As a result, the appropriate upper limit of normal 95th percentile for all ratios was 0.23 for men for all ages.  The establishment of appropriate reference ranges for TPSA and FPSA as well as ratios will allow the practicing urologist to incorporate these new parameters into diagnostic evaluation of men at risk for early, potentially curable prostate cancer.