There was an allegation of questionable elecsys free psa immunoassay results compared to elecsys total psa immunoassay results for 1 patient on a cobas e 801 analytical unit compared to a siemens analyzer.This medwatch will cover total psa.Refer to medwatch with a1 patient identifier pt (b)(6) for information on the free psa results.On (b)(6) 2024, the patient had a sample tested on module 3 free psa result of 1.23 ng/ml and a total psa result of 0.101 ng/ml.On (b)(6) 2024, the sample was repeated on a siemens analyzer and the free psa result was 0.03 ng/ml and the total psa result was 1.04 ng/ml.On (b)(6) 2024, the patient had a sample tested on module 4 and the free psa result was 1.20 ng/ml and a total psa result of 0.103 ng/ml.On (b)(6) 2024, the sample was repeated on a siemens analyzer and the free psa result was 0.03 ng/ml and the total psa result was 1.00 ng/ml.
|
The investigation did not identify a product problem.The specific cause of the event could not be determined.Based on the provided data, the issue was consistent with the presence of rare endogenous interfering substance(s) in the patient samples.Per product labeling: it is known that in rare cases psa isoforms do exist which 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.
|