Comparison of Three Assays for Total and Free PSA Using Hybritech and WHO Calibrations
Manuel M Garrido1,2, José C Marta3, Ruy M Ribeiro4
1Department of Clinical Pathology, Centro Hospitalar Universitário de Lisboa Central, Lisbon, Portugal; manuel.agarrido@chlc.minsaude.pt.
Background/Aim:
Lack of interchangeability between prostate-specific antigen (PSA) assays could have a clinical impact. We compared PSA assays from different manufacturers and calibrations.
Patients And Methods:
A total of 233 men who underwent prostate biopsy (PSA: 2-10 ng/ml; Beckman Coulter Access® Hybritech® as reference) were enrolled. Total (tPSA) and free PSA (fPSA) were also measured using the Roche cobas® and the Abbott Architect® methods.
Results:
Roche tPSA values were ≈1% higher than Beckman, while Abbott values were ≈5% lower. Roche had the highest diagnostic sensitivity (92%) compared to Beckman Coulter (87%) and Abbott (85%). Roche fPSA was ≈3% lower and Abbott ≈17% higher than that of Beckman. For the percentage of fPSA, Roche had the highest sensitivity (98%).
Conclusion:
Roche cobas® and Beckman Coulter Access® Hybritech® tPSA were almost interchangeable. While the agreement was acceptable for tPSA, this did not happen with fPSA and greater efforts for harmonization are required.
