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A literature article by moniuszko-malinowska anna, jelski wojciech, dunaj justyna, mroczko barbara, czupryna piotr, kruszewska ewelina, and pancewicz slawomir, ¿serology in covid-19: comparison of two methods¿, international journal of environmental research and public health 18.12 (jun 16, 2021), documented false negative sars-cov-2 igg results generated on the alinity i processing module.The aim of the study was to examine the performance of two assays in detecting sars-cov-2 antibodies.Two serological tests were used: sars-cov-2 igg cmia on the alinity system (abbott - for the qualitative detection of anti-n protein igg antibodies to sars-cov-2 in human plasma or serum) and liaison® sars-cov-2 s1/s2 igg clia (diasorin - for the quantitative determination of anti-s1 and anti-s2 specific igg antibodies to sars-cov-2).In total, 127 patients exposed to sars-cov-2 were included in the study.The diagnosis of sars-cov-2 infection was confirmed by reverse transcription polymerase chain reaction (rt-pcr) testing using the cfx96 real-time system (bio-rad) from nasopharyngeal swabs.Blood samples for immune-serological diagnosis were collected from all patients in the study one month after exposure.The anti-sars-cov-2 igg antibodies matched when detecting n and s protein in 123 of 127 (96.85%) patients.The results differed in only 4 of 127 cases in which the patients had mild covid-19 severity.Two of these cases generated false negative sars-cov-2 igg results on the alinity i processing module.No impact to patient management was reported.
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This report is being filed on an international product, list number 6r90-22 (sars-cov-2 igg) and has a similar product distributed in the us, list number 6r90-20/-30 (sars-cov-2 igg: eua # 200422/a001).Per article ¿serology in covid-19: comparison of two methods¿, 127 patients exposed to sars-cov-2 were included in the study.The diagnosis of sars-cov-2 infection was confirmed by reverse transcription polymerase chain reaction (rt-pcr) testing using the cfx96 real-time system (bio-rad) from nasopharyngeal swabs.Blood samples for immune-serological diagnosis were collected from all patients in the study one month after exposure.Discrepant negative results were generated using the abbott igg assay in comparison to positive results using the liaison® sars-cov-2 s1/s2 igg assay for 2 out of the 127 patients (1.6%) with mild covid-19 severity.Therefore, results for the study are within 95% ci (95.89, 100.00) for ppa for the assay.A direct comparison cannot be made between the abbott and liaison® assays as both detect a different protein to the virus and both use different test principles.The abbott sars-cov-2 igg assay is a chemiluminescent microparticle immunoassay (cmia) used for the qualitative detection of anti-n protein igg antibodies to sars-cov-2 in human plasma or serum whereas the liaison® sars-cov-2 s1/s2 igg uses chemiluminescence immunoassay (clia) technology for the quantitative determination of anti-s1 and anti-s2 specific igg antibodies to sars-cov-2.The complaint investigation for false negative sars-cov-2 igg results included a search for similar complaints, and the review of complaint text, trending data, labeling, scientific literature, and device history records.Return testing was not completed as returns were not available.In this case, the likely cause lot number is unknown and therefore in-house testing was not performed.Device history record review on list 6r90 did not show any nonconformances, potential non-conformances, or deviations.Labeling was reviewed and found to adequately address the issue under review.Labeling was reviewed which adequately address the issue under review.Per product labeling, negative results do not rule out sars-cov-2 infection, particularly in those who have been in contact with the virus.Follow-up testing with a molecular diagnostic should be considered to rule out infection in these individuals.Results should be used in conjunction with other data; e.G., symptoms, results of other tests, and clinical impressions.Results from antibody testing should not be used as the sole basis to diagnose or exclude sars-cov-2 infection or to inform infection status.To assess the clinical performance of the assay, a study was performed using 122 serum and plasma specimens collected at different times from 31 subjects who tested positive for sars-cov-2 by a polymerase chain reaction (pcr) method and who also presented with covid-19 symptoms.The positive percent agreement (ppa) at >/=14 days post-symptom onset is 100.00% (95% ci: 95.89, 100.00).Five specimens from 1 immunocompromised patient were excluded from the study.When the results from these specimens were included, the ppa at >/=14 days post-symptom onset was 96.77% (95% ci: 90.86, 99.33).This study was based on a hospitalized/symptomatic population.Differences in antibody responses between populations, based on more severe versus less severe illness, are consistent with published reports, zhao j et al.2020, "antibody responses to sars-cov-2 in patients of novel coronavirus disease 2019¿, medrxiv.Additionally, review of the manuscript, bryan et al.2020, ¿performance characteristics of the abbott architect sars-cov-2 igg assay and seroprevalence in boise, idaho¿, j.Clin.Microbiol, doi: 10.1128/jcm.00941-20., showed sensitivity data consistent with product labeling.125 patients who tested rt-pcr positive for sars cov-2 for which 689 excess serum specimens were available was tested and it was found that sensitivity reached 100% at day 17 after symptom onset and day 13 after pcr positivity.Emerging literature on sars cov-2 serology indicates that antibody responses to the virus decline over time.In some cases, this transient response results in the decline of both igg and neutralizing antibody titers.It remains unknown for how long antibodies persist following infection and if the presence of antibodies is indicative of protective immunity, seow et al, ¿https://doi.Org/10.1101/2020.07.09.20148429¿, and ou et al, ¿https://doi.Org/10.1101/2020.05.22.20102525¿.The publication, g.N.Maine et al, ¿longitudinal characterization of the igm and igg humoral response in symptomatic covid-19 patients using the abbott architect¿, journal of clinical virology 133 (2020) 104663.Https://doi.Org/10.1016/j.Jcv.2020.104663, demonstrated that the diagnostic sensitivity for the sars-cov-2 igg assay post symptom onset was 99.6 % at 4 to 5 weeks (peak test sensitivity).During the convalescent phase of the infection, a decline in the igg level was observed in patients who were followed for >100 days.Despite that decline, 92.3 % of the patient cohort remained igg positive 3¿6 months following symptom onset.Early studies in small cohorts of asymptomatic individuals or patients with mild covid-19 showed that 13¿40 % of them became seronegative in the early convalescent phase.This study was limited by using specimens from patients who mostly required hospitalization.There could be differences in the humoral response in patients that require admission to a hospital compared to those that are asymptomatic or only experience mild symptoms, as the igg response decays more rapidly in the latter population.Based on the investigation sars-cov-2 igg reagent is performing as intended, no systemic issue or deficiency of the sars-cov-2 igg reagent was identified.
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