Abbott Architect Method Principle definition
Abbott Architect Method Principle. The assay is an automated, two step immunoassay to detect qualitatively IgG antibodies to SARS-Cov-2 in plasma and serum samples using a chemiluminescent microparticle immunoassay (CMIS). The resulting chemiluminescent reaction is measured as a relative light unit (RLU). There is a direct relationship between the amount of the IgG antibodies to SARS-Cov-2 in the sample and the RLU detected by the system optics. The relationship is reflected in the calculated index (S/C). The presence or absence of the IgG antibodies to SARS-Cov-2 in the sample is determined by comparing the chemiluminescent RLU in the reaction to the calibrator RLU. Abbott Architect processes using a cut off index of 1.4, results <1.4 are interpreted as negative, results >1.4 are interpreted as positive. Boditech iCHROMA Method Principle: The test uses a sandwich immunodetection method; fluorescence labelled conjugates in a dried detection buffer binds to antibody in sample, forming antibody-antigen complexes, and migrates onto nitrocellulose matrix to be captured by the other immobilized anti-human IgG on test strip. The more antigen-antibody complexes lead to stronger fluorescence signal by the detector antigen which is processed by iCHROMA™.The iCHROMA™ processes the signal using a cut off index of 0.9 – 1.1, results <0.9 are interpreted as negative, results between 0.9 and 1.1 are interpreted as indeterminate and results >1.1 are interpreted as positive. Fifty plasma samples were collected from staff and patients of a GP practice with and without symptoms of Covid-19. The patients that were highly suspected on having Covid-19 had their swab samples taken and the samples were sent off to a private laboratory to have SARS-Cov-2 PCR assay done. The samples were run on the Abbott Architect 1 System using the SARS-CoV-2 IgG assay, 20 (40%) of the plasma samples assayed were identified as positive and the remaining 30 (60%) of the plasma samples assayed were identified as negative. The plasma samples were subsequently run on the iCHROMA using the Covid-19 antibody test. All the 20 positive samples (100%) were identified by the Boditech iCHROMA method as positive and 27 (90%) of the 30 negative samples were identified as negative by the Boditech iCHROMA method. The 3 negative samples identified by the Abbott SARS-CoV-2 IgG assay, as positive by the Boditech iCHROMA method might be due to the increased sensitivity of the Boditech iCHROMA method or reduced sensitivity of the Abbott SARS-CoV-2 I...