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A customer from outside the united states reported an observation of a depressed atellica im ca 19 9 (ca 19 9) result which was discordant relative to the diluted results.The calibration was valid and quality control (qc) recovered within the laboratory established ranges.The assay's instructions for use (ifu) states the following, under interpretation of results: "results of this assay should always be interpreted in conjunction with the patient's medical history, clinical presentation, and other findings." siemens is evaluating the event.
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Siemens filed initial mdr 1219913-2025-00052 on 14-mar-2025.Additional information (15-may-2025): siemens completed investigation for a customer observation of a depressed atellica im ca 19 9 (ca 19 9) result which was discordant relative to the diluted result.Siemens reviewed the instrument data and observed that the higher recovery seen upon dilution is not due to a prozone (high dose hook) effect.As specified in the assay procedure section of the atellica im ca 19-9 instructions for use (ifu) sample and solid phase are incubated together, followed by washing, before the lite reagent is added.Therefore, any unbound ca 19-9 present will be washed away so unbound ca 19-9 will not decrease signal by binding the lite reagent.Siemens assessed the data in accordance with atellica im ca19-9 design verification, where individual sample auto-dilution recoveries were compared to manual dilution recoveries.The performance of aim ca19-9 dilution recovery is consistent with the performance at time of design verification.Further, the siemens technical operations investigation into aim ca19-9 dilution recovery shows that the current performance is consistent with performance at the time of design verification.Further review of dilution recovery shows it is possible that some patient samples may exhibit dilution over-recovery with mucin/mucin-like assays such as ca 19-9.Additionally, it is important to understand the intended use of the assay is for monitoring, not for screening.The assay provides results from 1.20 ¿ 700 u/ml.Only samples with levels >700 u/ml should be diluted before retesting.A review of the assay control system materials shows assay performance has remained within specification within the past 2 years.Siemens investigated ca 19-9 dilution-recovery performance across multiple reagent lots, which included both manual and auto 1:10 dilutions with medical decision pool (mdp) level 5, which is commutable to patient samples, high calibrator lots c941h, c943h and c945h and high dose patient samples.Further investigation demonstrated that the ca 19-9 assay has met accuracy specifications for all internal control materials tested during lot-qualification testing of lots released within the past two years.It is noted that dilution-recovery performance is not consistent across all samples, and it is possible that some patient samples may exhibit dilution over-recovery with mucin/mucin-like assays such as ca 19-9.The product's instructions for use (ifu) states "sample-dependent nonlinear dilutions can be observed." additionally, it is important to note that the atellica im ca19-9 ifu states that the assay is useful as an aid in monitoring the status of patients having confirmed pancreatic cancer who have levels of serum at some point exceeding the median concentration.The assay is not intended for screening purposes and should always be used in conjunction with all other clinical and laboratory data.The assay provides results from 1.20 ¿ 700 u/ml.Only samples with levels >700 u/ml should be diluted before re-testing.The reported issue is resolved by the customer choosing to dilute all samples >500 u/ml.There is no evidence of a reagent or instrument issue and are performing according to specifications.The customer is operational, and the reported issue is resolved by routine troubleshooting.No further evaluation of this device is required.
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