Characteristics of Three Different Chemiluminescence Assays for Testing for SARS-CoV-2 Antibodies

Abstract

Several tests based on chemiluminescence immunoassay techniques have become available to test for SARS-CoV-2 antibodies. There is currently insufficient data on serology assay performance beyond 35 days after symptoms onset. We aimed to evaluate SARS-CoV-2 antibody tests on three widely used platforms. A chemiluminescent microparticle immunoassay (CMIA; Abbott Diagnostics, USA), a luminescence immunoassay (LIA; Diasorin, Italy), and an electrochemiluminescence immunoassay (ECLIA; Roche Diagnostics, Switzerland) were investigated. In a multigroup study, sensitivity was assessed in a group of participants with confirmed SARS-CoV-2 ( n = 145 ), whereas specificity was determined in two groups of participants without evidence of COVID-19 (i.e., healthy blood donors, n = 191 , and healthcare workers, n = 1002 ). Receiver operating characteristic (ROC) curves, multilevel likelihood ratios (LR), and positive (PPV) and negative (NPV) predictive values were characterized. Finally, analytical specificity was characterized in samples with evidence of the Epstein–Barr virus (EBV) ( n = 9 ), cytomegalovirus (CMV) ( n = 7 ), and endemic common-cold coronavirus infections ( n = 12 ) taken prior to the current SARS-CoV-2 pandemic. The diagnostic accuracy was comparable in all three assays (AUC 0.98). Using the manufacturers’ cut-offs, the sensitivities were 90%, 95% confidence interval [84,94] (LIA), 93% [88,96] (CMIA), and 96% [91,98] (ECLIA). The specificities were 99.5% [98.9,99.8] (CMIA), 99.7% [99.3,99.9] (LIA), and 99.9% [99.5,99.98] (ECLIA). The LR at half of the manufacturers’ cut-offs were 60 (CMIA), 82 (LIA), and 575 (ECLIA) for positive and 0.043 (CMIA) and 0.035 (LIA, ECLIA) for negative results. ECLIA had higher PPV at low pretest probabilities than CMIA and LIA. No interference with EBV or CMV infection was observed, whereas endemic coronavirus in some cases provided signals in LIA and/or CMIA. Although the diagnostic accuracy of the three investigated assays is comparable, their performance in low-prevalence settings is different. Introducing gray zones at half of the manufacturers’ cut-offs is suggested, especially for orthogonal testing approaches that use a second assay for confirmation.

Pathogenic Characterization of a Porcine Circovirus Type 3 Isolate from Heilongjiang, China

“…In our study, 5 of nine PCV3 DB-1 inoculated piglets showed an obvious trend in the IgG antibody response. The indirect ELISA method used in our study based on PCV3 recombinant rCap-VLPs [ 23 , 30 ] might conserve the conformational epitopes and had the ability to detect IgG antibodies against the conformational epitope of the PCV3. Antibodies against rCap-VLPs of PCV3 that appeared in piglets with a specific immune status may be inflammatory factors that alert immune cells to respond to the viral infection; however, whether these antibodies can neutralize PCV3 requires further investigation.…”

Dynamics of anti-SARS-CoV-2 IgG antibodies post-COVID-19 in a Brazilian Amazon population

“…The percentage of patients exhibiting antibody loss was high in the present study, which may have implications for seroepidemiological investigations [ 36 ], especially those conducted recently, possibly leading to underestimated calculations of the prevalence of infection or even the susceptibility of the population to possible reinfection and thus compromising the success of current vaccination campaigns. Therefore, the use of tests with high sensitivity and specificity as chemiluminescent microparticle immunoassay, can enhance the accuracy and capacity of diagnosis of anti-SARS-CoV-2 antibodies [ 37 ].…”

Evaluation of Dried Blood Spot Testing for SARS-CoV-2 Serology Using a Quantitative Commercial Assay

“…The clinical performance of the different commercial assays, such as Abbott SARS-CoV-2 (N) IgG, DiaSorin SARS-CoV-2 S1/S2 IgG, and Roche Elecsys Anti-SARS-CoV-2 (N), have been investigated, and sensitivity greater than 80% and specificity greater than 95% 14 weeks after confirmed infection have been reported in hospitalized patients. Slightly lower sensitivity for antibodies has been observed in outpatient settings [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. Roche Elecsys Anti-SARS-CoV-2 (S) is a quantitative assay that detects antibodies against the receptor-binding domain (RBD) with reported sensitivity of 84.0% 15–30 days post-PCR positivity, with no cross-reactivity leading to 100% specificity [ 47 ].…”