The customer reported a false negative reaction of a patient sample with a known anti-jk(a) when tested with biotest cell-i11 plus on tango infinity.The customer returned the supposedly defective product for investigational testing and also aliquots of two patient samples labelled patient a and patient b.According to the customer's documentation the aliquots of patient a contained an anti-jk(a) and the ones of patient b an anti-e.Because only very little material sent from patient b was available, our quality control laboratory could only test patient sample a with the returned complaint sample of biotest cell-i11 plus on tango infinity.All positive and negative reactions were correct.We did not observe any false negative reaction.Additionally the complaint sample was tested with different samples and controls, e.G.Anti-e and anti-jk(a) from an interlaboratory comparison test.Again, all results were as expected.Testing by our quality control laboratory confirmed that the allegedly defective lot of biotest cell-i11 plus functions correctly.A review of the batch record documentation showed no irregularities which might have negatively affected the quality of the allegedly defective lot.The affected tango infinity was inspected by our field service engineers with no indication for an instrument malfunction.The service engineer confirmed a proper function of the instrument by metrology qualification.Also the qc of other testing days was run without any issue.
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