tetano
Editor, Senior Moderator
J Clin Microbiol. 2020 Apr 10. pii: JCM.00375-20. doi: 10.1128/JCM.00375-20. [Epub ahead of print]
A method to prevent SARS-CoV-2 IgM false positives in gold immunochromatography and enzyme-linked immunosorbent assays.
Wang Q[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Du Q[SUP]1,[/SUP][SUP]3[/SUP], Guo B[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Mu D[SUP]4[/SUP], Lu X[SUP]1,[/SUP][SUP]3[/SUP], Ma Q[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Guo Y[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Fang L[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Zhang B[SUP]4[/SUP], Zhang G[SUP]5,[/SUP][SUP]3[/SUP], Guo X[SUP]5,[/SUP][SUP]2,[/SUP][SUP]3[/SUP].
Author information
Abstract
Objective: To investigate the interference factors that lead to false-positive novel coronavirus (SARS-CoV-2) IgM detected using gold immunochromatography assay (GICA) and enzyme-linked immunosorbent assay (ELISA) and the corresponding solutions.Methods: GICA and ELISA were used to detect SARS-CoV-2 IgM in 86 serum samples, including 5 influenza A virus (Flu A) IgM-positive sera, 5 influenza B virus (Flu B) IgM-positive sera, 5 Mycoplasma pneumoniae IgM-positive sera, 5 Legionella pneumophila IgM-positive sera, 6 sera of HIV infection patients, 36 rheumatoid factor IgM (RF-IgM)-positive sera, 5 sera from hypertensive patients, 5 sera from diabetes mellitus patients, and 14 sera from novel coronavirus infection disease (COVID-19) patients. The interference factors causing false-positive reactivity in the two methods were analyzed, and the urea dissociation test was employed to dissociate the SARS-CoV-2 IgM-positive serum using the best dissociation concentration.Results: Two methods detected positive SARS-CoV-2 IgM in 22 middle-high level RF-IgM-positive sera and 14 sera from COVID-19 patients; the other 50 sera were negative. When urea dissociation concentration was 6 mol/L, SARS-CoV-2 IgM were positive in 1 middle-high level RF-IgM-positive sera and in 14 COVID-19 patient sera detected using GICA. When urea dissociation concentration was 4 mol/L and the avidity index (AI) lower than 0.371 was set to negative, SARS-CoV-2 IgM were positive in 3 middle-high level RF-IgM-positive sera and in 14 COVID-19 patient sera detected using ELISA.Conclusion: Middle-high level of RF-IgM could lead to false-positive reactivity of SARS-CoV-2 IgM detected using GICA and ELISA, and urea dissociation tests would be helpful in reducing false-positive results of SARS-CoV-2 IgM.
Copyright ? 2020 Wang et al.
PMID:32277023DOI:10.1128/JCM.00375-20
A method to prevent SARS-CoV-2 IgM false positives in gold immunochromatography and enzyme-linked immunosorbent assays.
Wang Q[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Du Q[SUP]1,[/SUP][SUP]3[/SUP], Guo B[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Mu D[SUP]4[/SUP], Lu X[SUP]1,[/SUP][SUP]3[/SUP], Ma Q[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Guo Y[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Fang L[SUP]1,[/SUP][SUP]2,[/SUP][SUP]3[/SUP], Zhang B[SUP]4[/SUP], Zhang G[SUP]5,[/SUP][SUP]3[/SUP], Guo X[SUP]5,[/SUP][SUP]2,[/SUP][SUP]3[/SUP].
Author information
Abstract
Objective: To investigate the interference factors that lead to false-positive novel coronavirus (SARS-CoV-2) IgM detected using gold immunochromatography assay (GICA) and enzyme-linked immunosorbent assay (ELISA) and the corresponding solutions.Methods: GICA and ELISA were used to detect SARS-CoV-2 IgM in 86 serum samples, including 5 influenza A virus (Flu A) IgM-positive sera, 5 influenza B virus (Flu B) IgM-positive sera, 5 Mycoplasma pneumoniae IgM-positive sera, 5 Legionella pneumophila IgM-positive sera, 6 sera of HIV infection patients, 36 rheumatoid factor IgM (RF-IgM)-positive sera, 5 sera from hypertensive patients, 5 sera from diabetes mellitus patients, and 14 sera from novel coronavirus infection disease (COVID-19) patients. The interference factors causing false-positive reactivity in the two methods were analyzed, and the urea dissociation test was employed to dissociate the SARS-CoV-2 IgM-positive serum using the best dissociation concentration.Results: Two methods detected positive SARS-CoV-2 IgM in 22 middle-high level RF-IgM-positive sera and 14 sera from COVID-19 patients; the other 50 sera were negative. When urea dissociation concentration was 6 mol/L, SARS-CoV-2 IgM were positive in 1 middle-high level RF-IgM-positive sera and in 14 COVID-19 patient sera detected using GICA. When urea dissociation concentration was 4 mol/L and the avidity index (AI) lower than 0.371 was set to negative, SARS-CoV-2 IgM were positive in 3 middle-high level RF-IgM-positive sera and in 14 COVID-19 patient sera detected using ELISA.Conclusion: Middle-high level of RF-IgM could lead to false-positive reactivity of SARS-CoV-2 IgM detected using GICA and ELISA, and urea dissociation tests would be helpful in reducing false-positive results of SARS-CoV-2 IgM.
Copyright ? 2020 Wang et al.
PMID:32277023DOI:10.1128/JCM.00375-20