Age-specific reference intervals for Prostate-Specific-Antigen (PSA), its isoform-[-2] pro-PSA (p2PSA) and prostate health index in Indian males

Abstract

Background: Studies have shown that there are racial and age-group differences in Reference Intervals (RI) of total Prostate-Specific Antigen (tPSA), its isoform [-2] pro PSA(p2PSA) and % p2PSA, Free PSA(fPSA) and %f PSA, and Prostate Health Index (PHI), all of which have been used for screening and diagnosis of prostate cancer. Aim and Objectives: To establish age-specific Reference Interval (RI) for these markers in Indian males. Materials and Methods: Four hundred and six subjects with tPSA£4ng/ml and negative transabdominal prostate ultrasound findings formed the study group in whom the markers tPSA, p2PSA, fPSA were estimated and %p2PSA, %fPSA and PHI were calculated. Results: About 98 (24.1%) were £50 years, 182 (44.8%) were between 50 -59 years and 126 (31%) were 60 years. The mean of tPSA, fPSA, p2PSAand PHI in 60 years age group were significantly more than £50 years age group across all percentiles. The overall RI (2.5 - 97.5 percentiles) for p2PSA, % p2PSA and PHI were 1.29 - 12.52 pg/mL, 0.65 - 3.82 and 8.08 - 66.42 respectively. Though there were some changes in the RI as the age increased, the 90% confidence intervals of the groups overlapped with one another. Conclusion: There is need for establishing and validating the age specific RI in healthy subjects belonging to a particular race and ethnicity for any biomarker.

Keywords

• reference intervals
• prostate-specific antigen (psa)
• [-2] pro-psa(p2psa)
• prostate health index (phi)