Agreement between commercially available ELISA and in-house Luminex SARS-CoV-2 antibody immunoassays

  1. Rebeca Santano
  2. Diana Barrios
  3. Fàtima Crispi
  4. Francesca Crovetto
  5. Marta Vidal
  6. Jordi Chi
  7. Luis Izquierdo
  8. Eduard Gratacós
  9. Gemma Moncunill
  10. Carlota Dobaño

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

Serological diagnostic of the severe respiratory distress syndrome coronavirus 2 (SARS-CoV-2) is a valuable tool for the determination of immunity and surveillance of exposure to the virus. In the context of an ongoing pandemic, it is essential to externally validate widely used tests to assure correct diagnostics and epidemiological estimations. We evaluated the performance of the COVID-19 ELISA IgG and the COVID-19 ELISA IgM/A (Vircell, S.L.) against a highly specific and sensitive in-house Luminex immunoassay in a set of samples from pregnant women and cord blood. The agreement between both assays was moderate to high for IgG but low for IgM/A. Considering seropositivity by either IgG and/or IgM/A, the technical performance of the ELISA was highly imbalanced, with 96% sensitivity at the expense of 22% specificity. As for the clinical performance, the negative predictive value reached 87% while the positive predictive value was 51%. Our results stress the need for highly specific and sensitive assays and external validation of diagnostic tests with different sets of samples to avoid the clinical, epidemiological and personal disturbances derived from serological misdiagnosis.

Article activity feed

  1. Version published to 10.1038/s41598-021-98296-y
  2. ScreenIT

    SciScore for 10.1101/2021.03.09.21252401: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variableStudy population and sample selection: We analyzed 283 samples from peripheral blood from pregnant women and cord blood (Table 1).

    Table 2: Resources

    Antibodies
    SentencesResources
    After a washing step, they were incubated with peroxidase-conjugated detection antibodies (anti-human IgG or anti-human IgM+IgA) at 37°C for 30 min.
    anti-human IgG
    suggested: None
    anti-human IgM+IgA
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    A limitation of this study was the impossibility to stratify by days since onset of symptoms due to the small sample size. Ideally, performance validation should be done stratifying by days since onset of symptoms due to the kinetics of antibody production, which is delayed with respect to the onset of the infection. This is especially relevant in the case of IgG, which is the last immunoglobulin to develop during the course of an immune response. Therefore, the performance of a test highly depends on the time passed since the onset of infection, which can be monitored by the onset of symptoms or time since positivity of PCR in asymptomatic cases. In fact, our Luminex assay and others have demonstrated that performance reaches excellent levels at >10 o >14 days since onset of symptoms (6,21,22,27). Therefore, IgG SE assessment in this report would probably be higher had we stratified by days since onset of symptoms. Concerning IgG SP, the same studies report the following ranges: 53% (22), 90% (23), 83-95% (21), 96% (20) and 97% (27). None of these values are as high as the 99% SP reported here, although most of them reach a considerably high SP. With reference to IgM/A, the reported SE are as follows: 76-96% (22), 29-100% (27) and 77% (20). In this case, SE also increased with days since onset of symptoms and disease severity (22,27). The SE that we report here for IgM/A is concordant with the highest levels of those results. As for the SP, only one study reports a relativel...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2021.03.09.21252401v1 on medRxiv