Performance of the FREND™ COVID-19 IgG/IgM Duo point-of-care test for SARS-CoV-2 antibody detection

Abstract

Purpose : In the context of the current COVID-19 pandemic, multiple serological assays for the detection of severe acute respiratory syndrome 2 (SARS-CoV-2) immune response are currently being developed. This study compares the FREND TM COVID-19 IgG/IgM Duo (NanoEntec) a point of care (POCT) assay with the automated Elecsys anti-SARS-CoV-2 electrochemiluminescent assay (Roche Diagnostics). Methods: Serum samples ( n = 81) from PCR-confirmed SARS-CoV-2 positive patients at different time points after the onset of symptoms were analyzed with both assays. An additional 24 serum samples with cross reactivity potential were also included. Results: The sensitivity of the COVID-19 IgG/IgM Duo assay was higher as compared to the Elecsys anti-SARS-CoV-2 assay, especially when using the combined IgM/IgG result in samples analyzed within 6 days after the onset of symptoms (46.2% vs. 15.4%). The sensitivity of both assays increased with increasing time interval after the onset of symptoms and reached 100% for the COVID-19 IgG/IgM Duo assay in samples taken 14 days or more after symptom onset. Specificity of the COVID-19 IgG/IgM Duo assay was 95.8% for IgM, 91.7% for IgG and 87.5% for the combination of both. Conclusion: This study shows that the sensitivity of both assays was highly dependent on the time interval between the onset of the COVID-19 symptoms and serum sampling. Furthermore, rapid serological testing for SARS-CoV-2 antibodies by means of the FREND TM COVID-19 IgG/IgM Duo POCT assay showed a comparable diagnostic performance as the reference automated immunoassay.

Update on Rapid Diagnostics for COVID-19: A Systematic Review

“…Regarding serological tests POC and RDT for detecting antibodies, most showed high sensitivity and specificity values, indicating good clinical performance. However, we observed lower sensitivity values in tests that performed the analysis in the first days after SARS-CoV-2 infection [57,61,62,64] than in postinfection studies.…”

“…Among the 13 selected studies, 10 presented high values of sensitivity and specificity (>80%) [56][57][58]60,61,[64][65][66][67][68], and 1 reported 100% of sensitivity and specificity [56]. Lower sensitivity values were observed in the first days after infection [57,61,62,64] than the days postinfection. Accuracy was reported in three studies [56,63,65], and values lower than 80% were found only in the study by Fauziah et al [62].…”

“…Regarding immunoglobulin detection tests, we identified nine studies that assessed IgM and IgG levels [56][57][58][59][60][61][62][63][64], three evaluating only IgG [65][66][67], and one evaluating IgA, IgG, and IgM [68]. A total of 10 antibody tests were performed by lateral-flow assays (considering gold and fluorescence assays) [57][58][59][60][61][62][63][64][65]68], 1 by electrochemical enzyme immunoassay (ELISA) [56], 1 by magnetofluidic immuno-PCR platform [66], and 1 by the Split Luciferase (spLUC) antibody sensor [67].…”