New Year Message from the President
2021-01-01
A RUNX–CBFβ-driven enhancer directs the Irf8 dose-dependent lineage choice between DCs and monocytes
2021-02-18
Show all

Development of an Automated Chemiluminescence Assay System for Quantitative Measurement of Multiple Anti-SARS-CoV-2 Antibodies

Serological tests for COVID-19 have been instrumental in studying the epidemiology of the disease. However, the performance of the currently available tests is plagued by the problem of variability. We have developed a high-throughput serological test capable of simultaneously detecting total immunoglobulins (Ig) and immunoglobulin G (IgG) against nucleocapsid protein (NP) and spike protein (SP) and report its performance in detecting COVID-19 in clinical samples.

Date: 15 Jan 2021



Objectives: Serological tests for COVID-19 have been instrumental in studying the epidemiology of the disease. However, the performance of the currently available tests is plagued by the problem of variability. We have developed a high-throughput serological test capable of simultaneously detecting total immunoglobulins (Ig) and immunoglobulin G (IgG) against nucleocapsid protein (NP) and spike protein (SP) and report its performance in detecting COVID-19 in clinical samples.

Methods: We designed and prepared reagents for measuring NP-IgG, NP-Total Ig, SP-IgG, and SP-Total Ig (using N-terminally truncated NP (ΔN-NP) or receptor-binding domain (RBD) antigen) dedicated automated chemiluminescent enzyme immunoassay analyzer AIA-CL1200. After determining the basal thresholds based on 17 sera obtained from confirmed COVID-19 patients and 600 negative sera, the clinical validity of the assay was evaluated using independent 202 positive samples and 1,000 negative samples from healthy donors.

Results: All of the four test parameters showed 100% specificity individually (1,000/1,000; 95%CI, 99.63–100). The sensitivity of the assay increased proportionally to the elapsed time from symptoms onset, and all the tests achieved 100% sensitivity (153/153; 95%CI, 97.63–100) after 13 days from symptoms onset. NP-Total Ig was the earliest to attain maximal sensitivity among the other antibodies tested.

Conclusion: Our newly developed serological testing exhibited 100% sensitivity and specificity after 13 days from symptoms onset. Hence, it could be used as a reliable method for accurate detection of COVID-19 patients and to evaluate seroprevalence and possibly for surrogate assessment of herd immunity.

 

For inquiries regarding this press release

 

Sousuke KUBO

  • Department of Microbiology,
    Yokohama City University Graduate School of Medicine

    3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, Japan

Takeharu YAMANAKA

  • Professor
    Department of Biostatistics,
    Yokohama City University School of Medicine

    Department of Health Data Science,
    Yokohama City University Graduate School of Data Science

Akihide RYO

  • Professor
    Department of Microbiology,
    Yokohama City University Graduate School of Medicine

    3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, Japan