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The customer reported variable front type results on tango infinity.In one case (subject to this report) a false positive results in the negative control well when using erytype s abo confirm and erytype s abd+rev.A1, b on tango infinity.The sample was tested on (b)(6) 2025 at 10:29:48 and showed a false-positive result in the negative control well.The same sample was retested at 10:58:51, and the result returned correctly as expected (negative control: negative) by tango infinity.The customer did not provide samples of the affected products erytype s abo confirm and erytype s abd+rev.A1, b for investigational testing.Therefore, ur quality control laboratory tested their retention samples of the affected products erytype s abo confirm and erytype s abd+rev.A1, b.First, the plates were visually checked and showed no abnormalies or detachments of the coating.Then the complained lots of erytype s abo confirm and erytype s abd+rev.A1, b were tested with bromelin for erytype and erytypecell a1, b on the qc lab's tango infinity.One blood donor with blood group b was used for the positive specificity and 6 blood donors with blood group a rhd positive were used for negative specificities.All samples reacted specifically according to their blood type.We confirmed that the products used in the customer's tests did not exhibit any discrepant results during quality control testing.We can confirm that there are no manufacturing-related quality issues with the materials involved in this complaint.The trace files of the affected tango infinity were analyzed.Our investigation suggests this issue was caused by splashing during strip transport from the incubator to the centrifuge.The data analysis confirmed that needle carry-over was not involved; instead, splashing during strip movement is considered the cause.This also aligns with the troubleshooting performed by the customer, who mentioned that cleaning the manifold immediately after noticing this issue resolved it.After reviewing pipetting logs for year 2024 samples, we found no additional occurrences of carry-over in any negative control wells, confirming this as an isolated incident.We identified two specific carry-over issues for this complaint (see also report 9610824-2025-09).To avoid similar occurrences of carry-over in the future, we recommend to the customer taking the following actions: check the centrifuge entrance for splashes.If splashes are detected, adjust transitions to ensure smooth movement during strip transfer.Inspect the linear shaker for splashes and verify linear shaking teaching settings; adjust if necessary.Examine the needle tip for damage by performing a high dispense test over the rinsing station and checking water beam integrity.Conduct a visual inspection of dispensing operations within the linear shaker to identify potential issues.
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