Lessons learned: A look back at the performance of nine COVID-19 serologic assays and their proposed utility.

Background: Serologic assays for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been proposed to assist with the acute diagnosis of infection, support epidemiological studies, identify convalescent plasma donors, and evaluate vaccine response.

Methods: We report an evaluation of nine serologic assays: Abbott (AB) and Epitope (EP) IgG and IgM, EUROIMMUN (EU) IgG and IgA, Roche anti-N (RN TOT) and anti-S (RS TOT) total antibody, and DiaSorin (DS) IgG. We evaluated 291 negative controls (NEG CTRL), 91 PCR positive (PCR POS) patients (179 samples), 126 convalescent plasma donors (CPD), 27 healthy vaccinated donors (VD), and 20 allogeneic hematopoietic stem cell transplant (HSCT) recipients (45 samples).

Evaluation of Three Commercial and Two Non-Commercial Immunoassays for the Detection of Prior Infection to SARS-CoV-2.

Background: Serological testing provides a record of prior infection with SARS-CoV-2, but assay performance requires independent assessment.

Methods: We evaluated 3 commercial (Roche Diagnostics pan-IG, and Epitope Diagnostics IgM and IgG) and 2 non-commercial (Simoa and Ragon/MGH IgG) immunoassays against 1083 unique samples that included 251 PCR-positive and 832 prepandemic samples.

Results: The Roche assay registered the highest specificity 99.

Different indirect immunofluorescence ANA substrate performance in a diagnostic setting of patients with SLE and related disorders: retrospective review and analysis.

Objective: Given the increasing relevance of the ANA assay to classification of SLE and the uncertainty and variation surrounding different ANA assay performance, we compared the human epithelial type 2 (HEp-2) to mouse liver (ML) substrate in our local cohort and provided a review of the evidence for their use in autoimmune rheumatic diseases (ARDs).

Methods: Electronic health record data (2003-2008) were used to identify patients who had concurrent HEp-2 and ML ANA, and a diagnosis of SLE or other ARDs. We determined the agreement between HEp-2 and ML ANA regarding positivity, titre and pattern, and their predictors.

A comparative study on clinical and serological characteristics between patients with rhupus and those with systemic lupus erythematosus and rheumatoid arthritis.

Background: The concomitant presence of two autoimmune diseases - systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) - in the same patient is known as rhupus. We evaluated a group of patients with rhupus to clarify further their clinical, serological and immunogenic features in a multi-centre cohort. In addition, the study aimed to explore the utility of the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) SLE classification criteria in our group of patients with rhupus.