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A customer from (b)(6) notified biomérieux that they experienced a false negative result on a patient sample when using vidas® lyme igm 60 tests (ref 30319, lot 1008391150, expiry date 26oct2021).The patient is a woman (b)(6) years old who was bitten by a tick (b)(6) 2020; after a few days, she observed an erythema on the skin.At a separate laboratory (not this biomérieux customer site), the patient was tested positive via lyme igm (method not reported) on (b)(6) 2020.She received treatment with azithromycin based on this result.On (b)(6) 2021, the customer reported that they obtained negative vidas lyme igm results on (b)(6) 2021 as follows : vidas lyme igm (211026-0) = 0.07 tv; vidas lyme igg (210904-0) = 0.00 tv.Western blot test (euroline-rn-at from euroimmun) from the same sample was positive.To be noted that the patient has been tested (date not reported) on vidas sars cov2 igg and was positive.At the time of this assessment, there is no information from the customer that this event led to an impact to the patient health.A biomérieux internal investigation has been initiated.
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This report was initially submitted following notification from a customer in poland regarding a false negative result on a patient sample when using vidas® lyme igm 60 tests (ref (b)(4), lot 1008391150, expiry date 26oct2021).A biomérieux internal investigation has been completed with the following results: device history record: the analysis of the batch history records of vidas lyme igm lot 1008391150/211026-0 showed no anomaly during the manufacturing, control and packaging processes.Tests/analysis performed: the customer¿s sample was received frozen and the remaining volume was more than 3 ml (2 tubes).Analysis of control chart: analysis was performed on seven (7) vidas lyme igm batches including the batch used by the customer (lot 1008391150/211026-0).Five (5) internal samples including two (2) samples with a negative target (0.01 and 0.07 tv), one equivocal ( 0.28) and two (2) positive (1.22 and 2.29 tv) were tested.All the results were in accordance with the expected specifications and vidas lyme igm lot 1008391150/211026-0 was in the trend of the other lots.Tests performed by complaint laboratory: tests on internal sample in complaint laboratory.Two (2) samples with the targets at 0.39 and 0.44 (close to the positive cut off) were tested on vidas lyme igm lot 1008391150/211026-0 (retain kit).According to these results, there is no evolution over time of vidas lyme igm lot 1008391150/211026-0.Tests on customer¿s sample: the complaints laboratory tested the patient¿s sample on vidas lyme igm lot 1008391150/211026-0 (batch mentioned by the customer) and another batch 1008136160 / 210605-0 manufactured with other raw materials.The negative result was reproduced on both batches and with similar results to the customer.Therefore, the negative result is not linked to a specific batch of vidas lyme igm.The sample was tested in an external laboratory, on liaison xl diasorin.Results: igg <5 au / ml igm = 24 au / ml interpretation: absence of igg, presence of igm.The liaison xl diasorin method for borreliosis serological diagnosis indicated the presence of igm with a positive value but close to the cut-off.Root cause analysis and conclusion: according to all information above, no anomaly was highlighted with the control chart analysis, the analysis of quality data and the tests performed on the internal sample with retain kit vidas lyme igm lot 1008391150/211026-0.The negative result was reproduced when testing the customer¿s sample using vidas lyme igm.The negative result was not linked to a specific batch of vidas lyme igm.The western blot method, ie euroimmun, gave a positive result but could be interpreted as borderline result due to the absence of vlse band.The other serological method, liaison xl diasorin, gave a positive result but close to the positive cut off.The negative result observed with vidas lyme igm method could be interpreted by a level of antibodies below the positive cut off of the method leading to a negative interpretation.It is mentioned in the package insert at section limitations of the method: "¿ negative results with the vidas® lyme igm and vidas® lyme igg assays does not rule out the possibility of b.Burgdorferi infection in a patient.Patients in the early stages of infection or who have undergone antibiotic therapy, may not produce measurable igm and igg.Patients with clinical history and/or symptoms suggestive of lyme borreliosis, but with negative test results, should be reported as "no detectable antibodies to b.Burgdorferi".A second specimen should be collected 4-6 weeks later.Clinical symptoms, epidemiological information and other laboratory test results must all be considered when interpreting vidas® lyme igm and igg assay results." as mentioned in the cdc guideline: ¿ antibodies normally persist in the blood for months or even years after the infection is gone; therefore, the test cannot be used to determine cure.Infection with other diseases, including some tickborne diseases, or some viral, bacterial, or autoimmune diseases, can result in false positive test results.Some tests give results for two types of antibody, igm and igg.Positive igm results should be disregarded if the patient has been ill for more than 30 days.The concerned sample had a specific antibodies profile: no igg, an igm antibody level close to the diasorin cut off and a confirmatory test, euromimmun western blot, borderline.The clinical context may explain this antibody profile due to the age of the infection (october 2020) and the antibiotic therapy prescribed before the vidas serological tests.The hypothesis of the issue is linked to the clinical context of the patient with a potential serological scar.According to the information mentioned above, vidas lyme igm lot 1008391150/211026-0 is meeting its specifications.
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