[120712756]
Customer has reported ((b)(4)) to the technical sale specialist on (b)(6) 2018 that drop out of probes 202 and 207 was experienced on the dqa locus while using lifecodes hla-dqa1/b1 sso typing kit lot number 3006117 leading to false dqa allele assignments. They indicated the loss of one or both of these probes may affect the dqa1*02 identification. Two scenarios were exhibited: (1)drop out of probes 202 and 207 led to an exact homozygous assignment for dqa with complete miss of the expected dqa1*02 antigen. (2)result generated with "review probes" which assigned the expected dqa1*02 as part of an ambiguous string. The customer indicated they have seen this problem with prior lots of the product but raise the issue now because it is getting worse. Customer is currently performing an internal investigation to check for mistyped dqa1* patients in relation to donor specific antibodies for renal transplant patients. Immucor field support visited the customer on august 20, 2018 and identified that the customer is using the product off-label. They are processing the samples using a half volume protocol for both the pcr and the hybridization steps and they do not heat the probe mix before use. Remaining steps, equipment used, reagent storage were followed per the instructions for use (ifu). The four samples exhibiting the drop out probes were re-tested using volumes indicated in the ifu for the hybridization step. The testing was performed in duplicate, one with full volume beads as directed per the ifu and one with half volume beads. For both testing events , the probe mix was not heated to 55 degrees before use. The results of these tests showed technically valid runs with both the full and the half volumes hybridization steps. For the dqa runs there were no significant changes to the mfis in comparison to the original run performed but in 2 of the 4 samples the match type was changed to "review probes" from exact with no allele assignments. On the other two samples it made no difference to the match type and both had the same assignments similar to when they were tested the first time. In all four samples getting the expected dqa1*02 will require changing probe 202 which was more than 70% far from the probe cut offs. On august 21, 2018, the four samples were re-tested again using the ifu protocol with full volumes for both pcr and hybridization, probe mix heating and a new lot of taq polymerase enzyme. The run was technically valid with significantly improved mfis of the consensus probe 200, probe 202 and probe 207. This repeat testing gave exact match type for all four samples with the expected dqa1*02.
Patient Sequence No: 1, Text Type: D, B5