The customer received questionable high ca 15-3 results for two patient samples where various scans on the patients were negative.Of the data provided, only one patient was tested with the elecsys ca 15-3 ii assay.The patient had breast cancer in 2010 treated by surgery, radiotherapy, and hormone therapy and was monitored for ca 15-3 using the kryptor-brahms method.On (b)(6) 2015, the ca 15-3 result was 30.9 ku /l.The breast mri was normal and the patient was well.On (b)(6) 2015, the ca 15-3 result was 32.8 ku /l.In (b)(6) 2015, the patient had a tep that was a normal scan.On (b)(6) 2016, the ca 15-3 result was 97.8 ku /l, which triggered a new pet scan that showed nothing.In (b)(6) 2017, the patient had a bone scintigraphy with nothing to report.On (b)(6) 2017, the ca 15-3 result was 260.5 ku /l.As the ca 15-3 results increased but many imaging tests were negative, the customer suspected interference.Dilutions of the samples were performed and did not change the results.On (b)(6) 2017, two of the samples were repeated using the elecsys ca 15-3 ii assay and a cobas 6000 e 601 module.The serial number of the analyzer was requested, but it was not provided.The sample from (b)(6) 2017 had a result of 300.0 ku/l with a data flag and 280.1 ku/l with a 1:10 dilution.The sample from (b)(6) 2016 had a result of 113.4 ku/l and 111.2 ku/l with a 1:10 dilution.Testing using an hbt tube was negative.The presence of rheumatoid factors (igm and iga) was found to be negative.All of the results were reported outside the laboratory.There was no allegation of an adverse event.
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