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Background: The description of a new method for the measurement of complexed prostate-specific antigen (cPSA) offers a new approach to the diagnosis of prostate cancer., Patients and Methods: We measured PSA (Hybritech and Bayer), free PSA (Hybritech) and complexed PSA (Bayer) in 72 patients with prostate cancer and 128 with benign prostate hyperplasia., Results and Conclusion: We found an increase of sensitivity using 25 and 7 ng/mL as cut-offs for cPSA in relation to total PSA using as cut-offs 4 and 10 ng/mL (96 and 36% vs. 92 and 35.5%). Similar differences were found for specificity (78% and 31% for cPSA vs. 73% and 29% for total PSA). Therefore, we defined a gray zone for patients with cPSA between 2.5 and 7 ng/mL for which the measurement of the free/complexed PSA ratio saves an important number of negative biopsies maintaining a higher sensitivity.

Objectives: To compare the diagnostic efficacy of prostate-specific antigen (PSA) and the PSA fractions (free PSA [fPSA] and complexed PSA [cPSA]) in the differential diagnosis between prostate cancer and benign prostatic hyperplasia., Methods: We measured the serum levels of total PSA (tPSA; Hybritech and Bayer), fPSA (Hybritech), and cPSA (Bayer) in 72 patients with prostate cancer and 128 patients with benign prostatic hyperplasia., Results: Receiver operating characteristic curves were used for comparison of these tests. The greatest area under the curve was observed for the fPSA/cPSA ratio and the fPSA/tPSA ratio (0.757 and 0.754, respectively). The substitution of the fPSA/tPSA ratio with the fPSA/cPSA ratio in the diagnostic scheme of prostate cancer improved the diagnostic accuracy, with similar sensitivity and an increment in specificity (41% versus 45%)., Conclusions: The fPSA/cPSA ratio ensures a reduction in negative biopsies in the PSA gray zone. We suggest substituting the fPSA/tPSA ratio with the fPSA/cPSA ratio for patients with a PSA level between 4 and 10 ng/mL.

Background and Objective: The description of different forms of PSA has opened a new strategy in the diagnosis of prostate cancer. The measurement of the ratio between free PSA and PSA in the group of patients with a PSA level between 4 and 10 ng/ml decreases the number of negative biopsies. The aim of our study was to compare the diagnostic efficacy of PSA and PSA fractions (free PSA [fPSA] and complexed PSA [cPSA]) in the differential diagnosis between Pca and benign prostate hyperplasia (BPH)., Patients and Method: We measured the serum levels of PSA, free PSA and cPSA in 56 patients with Pca and 94 patients with BPH., Results: ROC curves were used for the comparison of tests. The biggest area under the curve (AUC) was observed for the ratios fPSA/cPSA and fPSA/PSA (0.718 and 0.712, respectively). When we compared the AUC between PSA and cPSA, then AUC for cPSA was higher than AUC for PSA (0.602 and 0.567, respectively). We observed similar results in the group of patients with PSA levels between 4 and 10 ng/ml., Conclusions: The diagnostic accuracy of cPSA is higher than that of PSA. Moreover, in the differential diagnosis between prostate cancer and BPH, the use of PSA ratios (fPSA/cPSA or fPSA/PSA) increases the diagnostic accuracy obtained with the measurement of PSA or cPSA.