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COVID-19 Human IgA ELISA kit (Nucleocapsid Protein)


96T ¥150,000

​(tax excluded)

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Measurement method : Indirect ELISA
Measurement wavelength : 450 nm
Measurement sample : Serum, saliva, sputum
Species reactivity : Human
Storage temperature : Store at 2-8° C. 
Expiration date : 12 months after production
Immobilized antigen : SARS-CoV-2 Nucleocapsid protein (Full length, E. coli expression system)

Kit contents

1. SARS-CoV-2 nucleocapsid protein-immobilized plate

2. HRP-conjugated anti-human IgA antibody

3. Washing buffer(10× PBST)

4. Bovine serum albumin (for diluent buffer)

5. Diluent buffer (10×)

6. R-1: Chromogenic substrate (TMB)

7. R-2: Stop reagent (1 mol/L hydrochloric acid)

8. Microplate seal


10 μL×1

100 mL×1


50 mL×1

22 mL×1

22 mL×1


Measurement principle

  1. The SARS-CoV-2 recombinant nucleocapsid protein immobilized on the plate is recognized and reacted with the antibody (hereinafter, abbreviated as anti-nucleocapsid protein antibody) in a sample.

  2.  After the reaction, the sample is removed by washing

  3.  The anti-spike protein antibody is reacted with HRP (Horseradish peroxidase)-conjugated anti-human IgA antibody

  4. Remove excess HRP-conjugated anti-human IgA antibody by washing. Add a chromogenic substrate and measure the absorbance.

IgA 原理図.png

Significance of measurement

This kit is a research ELISA kit to detect human IgA antibody that recognizes the nucleocapsid protein of SARS-CoV-2, the causative virus of Covid-19.
Virus detection can be broadly divided into two approaches: one is to detect the virus itself, such as PCR method, and the other is to detect the immune response that develops during infection (IgG, IgM, IgA). IgA is particularly abundant in mucous membranes such as saliva and the nasopharynx, and generally has the function of infection prevention.

Related literature

      PLoS One. 2021 Apr. PubMed PMID: 33909646

      J Clin Lab Anal. 2021 Feb. PubMed PMID: 33608968

      Transfusion. 2020 Dec. PubMed PMID: 32935877

      J Clin Microbiol. 2020 Dec. PubMed PMID: 32917729

      Sci Rep. 2020 Nov. PubMed PMID: 33257702

      Res Sq. 2020 Aug 14. PubMed PMID: 32818217

      Cochrane Database Syst Rev. 2020 Jun 25. PubMed PMID: 32584464

     Viruses. 2020 May 26. PubMed PMID: 32466458


1.)Keiichi Hiramatsu, Standard Textbook of standard microbiology, 11th edition, Medical study (2012)

2.)Andrea Padoan, IgA-Ab response to spike glycoprotein of SARS-CoV-2 in patients with COVID-19: A longitudinal study, Clinica Chimica Acta, 507, 164-166, Aug., 2020

3.)Yin Xia Chao, The role of IgA in COVID-19, Brain, Behavior, and Immunity, 87, Jul., 2020 

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