Abstract

Aim: To evaluate the diagnostic performance of free-total PSA ratio using the criteria of total PSA > 4.0 ng/ml as the cut-off for prostate cancer diagnosis in men. Method: A total of sixty patients (mean age 58.03 ± 9.82) were recruited as test subjects from the cancer unit of National Obstetric Fistula Center (NOFIC), Abakaliki, Ebonyi State, Nigeria. All the patients had total PSA value above 4.0ng/ml. Free and total PSA estimations were done using the principle of Enzyme Linked Immunosorbent Assay (ELISA). Result: Free-total PSA ratio indicated high sensitivity (98.2% and 98.2%), specificity (87.9% and 82.9%) and positive predictive values (93.3% and 90%) for detecting undiagnosed prostate cancer at cut-offs of 0.25 and 0.19 respectively. High sensitivity (97.6%) and moderate specificity (61.7%) and positive predictive value (70.0%) were observed at cut off of 0.10. Using the free-total PSA ratio cut-off of ≤ 0.10 for prostate cancer, 70% of the test subjects were diagnosed of prostate cancer, on the other hand when a cutoff of > 0.25 was used, 6.7% of the test subjects were diagnosed of a possible benign prostatic hyperplasia.
Conclusion: Free-total PSA ratio is a highly sensitive, specific and useful diagnostic tool alternative to total PSA assay for the screening of undiagnosed prostate cancer. Furthermore, it is highly predictive of the risk for developing prostate cancer at specific cutoff levels.

Key words: : Prostate-Specific Antigen (PSA), Free-Total PSA Ratio, Prostate Cancer