Need for Age-Specific Prostate-Specific Antigen Reference Intervals in a Nigerian Population

Background: In Nigeria, the diagnostic value of prostate-specific antigen (PSA) is a matter of debate. PSA levels are known to vary with population, environmental factors, and advancing age. Studies suggest age-specific reference intervals (ASRIs) of PSA value are more accurate than single cut-off PSA value. For ASRIs to be used effectively, reference intervals (RIs) must be fully evaluated.Aim: We determine ASRIs in a Nigerian population.Materials and Methods: The study was carried out from January 2016 to January 2019 among 660 adult Nigerian men aged 30-86 years old in Enugu State. Participants completed questionnaire demographics and previous screening. Age group was the indicator. Among them, a total 24 (3.6%) were excluded. Data from 636 (96.4%) men were analyzed for ASRIs. Estimation of PSA was done as per the International Federation of Clinical Chemistry Guideline. Spearman correlation was used to identify correlates P values < 0.05 which was considered significant.Results: The mean age group was 49.6 +/- 10.2 years. ASRIs using 95(th) percentile, and PSA values in each 10 years groups were 0-1.94 ng/ml (median 0.22), 0-2.52 ng/ml (median 0.42), 0-3.52 ng/ml (median 1.06), 0-4.8 ng/ml (median 2.1), 0-6.95 ng/ml (median 4.1), and 0-5.6 ng/ml (median 2.4), for age groups 30-39, 40-49, 50-59, 60-69, 70-79, and <= 80 years, respectively. There was positive correlation between PSA and age (r = 0.9915, P < 0.0001). Low income and educational background were more prevalent among the study group.Conclusion: Our study provided the ASRIs in our environment but higher than single cut-off value. The data recommended PSA values should be characterized by age and ethnicity.