MP21-03 HOW ACCURATE IS THE PSA TEST? A PREVALENCE STUDY OF DISTURBED PSA VALUES IN A TERTIARY REFERRAL HOSPITAL

Abstract

You have accessJournal of UrologyProstate Cancer: Detection & Screening III1 Apr 2016MP21-03 HOW ACCURATE IS THE PSA TEST? A PREVALENCE STUDY OF DISTURBED PSA VALUES IN A TERTIARY REFERRAL HOSPITAL Cedric Poyet, Karim Saba, Noemie Lautenbach, Lanja Saleh, Martin Umbehr, Tullio Sulser, Michael Müntener, and Arnold von Eckardstein Cedric PoyetCedric Poyet More articles by this author , Karim SabaKarim Saba More articles by this author , Noemie LautenbachNoemie Lautenbach More articles by this author , Lanja SalehLanja Saleh More articles by this author , Martin UmbehrMartin Umbehr More articles by this author , Tullio SulserTullio Sulser More articles by this author , Michael MüntenerMichael Müntener More articles by this author , and Arnold von EckardsteinArnold von Eckardstein More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.637AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Prostate specific antigen (PSA) is of paramount importance for the detection and monitoring of patients with prostate cancer. We and others have reported artifical altered PSA levels due to the presence of heterophilic antibodies (hA). Unrecognized artifical high PSA levels due to hA can lead to severe overtreatment of patients. The prevalence of altered PSA levels due to hA interference or other factors is unknown. METHODS Recoveries of all PSA samples taken consecutively in our hospital from February to May 2014 using a 3rd generation electrochemoluminescence assay (ECLIA) from Roche diagnostics were determined by diluting the patient samples with a standard serum of known PSA concentration. Samples with recoveries <80% or >130% of the expected values were retested and PSA was determined again after adding a blocking reagent for hAs (Scantibodies Laboratory, Santee, CA). RESULTS A total of 1500 serum probes were consecutively analyzed. Four out of 1500 probes (0.27%) showed reproducibly disturbed recoveries. Two samples showed falsely-elevated PSA values (Sample 1: 62.5-fold falsely-elevated; Sample 2: 1.6-fold falsely-elevated). The other two samples showed falsely-low PSA values (Sample 3: 8263-fold falsely-decreased; Sample 4: 31-fold falsely-decreased) (Table 1). After pretreatment of the patient sera with a blocking reagent for hAs, 3 out of 4 samples showed normal recoveries. Sample 3 could not be reanalyzed because of lack of original sample material and patients death. CONCLUSIONS We conclude that about 0.3% of PSA tests by the 3rd generation Roche are disturbed. Although a very rare event this interference puts a relevant amount of patients worldwide at risk of over- or underdiagnostics. Manufacturers and clinical laboratories should know the rates and kinds of interference for their PSA test used. In case of clinically implausible high or low PSA levels, clinicians should rule out sampling errors and repeat PSA tests by including determinations of recoveries, and, if pathological, absorbing hA in the serum of the patients. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e245 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Cedric Poyet More articles by this author Karim Saba More articles by this author Noemie Lautenbach More articles by this author Lanja Saleh More articles by this author Martin Umbehr More articles by this author Tullio Sulser More articles by this author Michael Müntener More articles by this author Arnold von Eckardstein More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...