In a recent issue of American Society for Clinical Pathology, Mayo Clinic's Eric Klee, Ph.D., Olga Bondar, Ph.D., Marcia Goodmanson, Sergey Trushin, Ph.D., Ravinder Singh, M.D. and George Klee, M.D., Ph.D. created the article, "Mass Spectrometry Measurements of Prostate-Specific Antigen (PSA) Peptides Derived From Immune-Extracted PSA Provide a Potential Strategy for Harmonizing Immunoassay Differences."
The article discusses why the harmonization of prostate-specific antigen (PSA) immunoassays is important for good patient care. The specificity of the antibodies used to detect circulating PSA could cause differences in the PSA measurements.
According to the article, PSA measurements from the immunoassays and the MS peptide assays were highly correlated (R2 > 0.99), but the recovery of the World Health Organization standard and the regression slopes differed across assays. The same relative patterns of immunoassay differences were seen in comparing their results with each of the MS peptide measurements from different parts of the circulating PSA molecules.
As a result from their findings, mass spectrometry quantitation of peptides derived from trypsin digestion of immune-extracted PSA could be used to harmonize PSA immunoassays.