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The patient sample was received for investigation.The investigation confirmed the customer's elecsys total psa (total psa) and elecsys free psa assay results.The investigation tested the patient sample for interferents using dilution tests, heterophil antibody testing (hbt), spiking treatment, and rf ii tests.The dilution and spiking treatment tests detected the tpsa auto-antibody or tpsa isoform against total psa in the patient sample; no interferent was detected in the heterophil antibody testing (hbt) and rf ii tests.Elecsys total psa (total psa) product labeling states, "in rare cases, interference due to extremely high titers of antibodies to analyte-specific antibodies, streptavidin or ruthenium can occur.These effects are minimized by suitable test design.It is known that in rare cases, psa isoforms do exist that may be measured differently by different psa tests.Findings of this kind have occasionally been reported for psa tests from various manufacturers.For diagnostic purposes, the results should always be assessed in conjunction with the patient¿s medical history, clinical examination and other findings." elecsys free psa product labeling states, "in rare cases, interference due to extremely high titers of antibodies to analyte-specific antibodies, streptavidin or ruthenium can occur.These effects are minimized by suitable test design.For diagnostic purposes, the results should always be assessed in conjunction with the patient¿s medical history, clinical examination and other findings." the investigation determined that an interferent and rare isoform had caused the event.The investigation did not identify a product problem.
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