An investigation determined that a software bug causes the generation of duplicate unique slide identifiers (usids) for internal orders entered directly into the system software.The issue does not apply to external orders received from the customer's laboratory information system (lis).The system software generates the usids/barcodes for new internal orders based on several factors, including the host id and the value of the last barcode allocated.The value of the last barcode allocated in the software's configuration table determines the usid/barcode value to be utilized for the next new order.With each internal order, the value of one (1) is added to the last barcode allocated, and the new value is stored in the table.This value updates normally when the last barcode allocated is between 0 to 99,999.Once the value reaches 99,999, new internal orders will start incrementing beginning at 99,999.This leads to a range of uisds being recycled or reused, hence the term "duplicate" usids.Even though usids are duplicated by the software, this alone does not cause inappropriate staining and requires other factors such as: -the end user creates an order in the software, prints a slide label, and then deletes the order in the software without discarding the initial label.-a completed slide is reinserted into the instrument.There are no user actions that can modify the last barcode allocated value.Data analysis showed internal printed slide labels consisting of the usid/barcode: "ve0376c001896a" were scanned more than once by the staining instrument barcode scanner.The data verifies a "duplicate usid" event occurred for the alleged slides.Customers have been notified of the issue and the issue is addressed in a new software update.There are several mitigating factors that allow the detectability of this scenario: the expected staining pattern of the intended assay, the use of the same slide and/or internal positive controls, comparison of the label to the run report which will show a protocol mismatch, and interpretation in conjunction with other relevant clinical information and assay results.
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