Full Name: SARS-CoV-2 NP IgA ELISA Kit
Reactivity: Human
Sample Type: Serum, Plasma
Sensitivity: Qualitative


SARS-CoV-2 was a global disease that emerged and spread quickly during 2019, it posed a huge treat to the world health and safety. This virus consists of four structural proteins; M (membrane), S (spike), E (envelope) and NP (nucleocapsid protein). The pathophysiology of SARS-CoV-2 is not well understood, but it has been found that the virus mimics a type of coronavirus called an astrovirus. This is associated with cold symptoms and could cause fever, pneumonia or septic shock in humans. The respiratory route is the predominant route of transmission.

The nucleocapsid protein is responsible for assembling with the viral RNA to form the helical ribonucleoprotein complex. The NP is known to associate with the positive stranded RNA genome and the M protein, this is essential for the virus to replicate. The nucleocapsid is the most abundant protein present within the coronavirus particle, and is composed of a helix of secondary structural elements and loops. The viral RNA genome encapsidues the nucleocapsid protein in a helical symmetry. The ribonucleoprotein is then assembled around the protein, as well as with M-protein. This complex has a very critical role in assembly of the virus, mutation can cause premature release of virus particles and replication inhibition.


Human SARS-CoV-2 NP IgA ELISA kit can measure IgA class of antibodies against nucleocapsid protein (NP) of the SARS-CoV-2 virus in serum and plasma.


Each kit contains the following components and is sufficient for 96 tests.

  • One Aluminium Pouch: Containing microwell plate bound with SARS-CoV-2 NP protein.
  • 10x Wash Buffer.
  • 5x Assay Buffer.
  • 100x Detection Antibody Solution: HRP coated anti IgA monoclonal antibody.
  • 10x Positive Control.
  • Substrate Solution.
  • Stop Solution.
  • Blank Control.


Healthy Patients:
Blank Control: 0.076 (OD450).
Serum From Healthy Subjects: 0.172, 0.189, 0.204, 0.164, 0.172, 0.211, 0.245, 0.17, 0.104, 0.204, 0.105, 0.105, 0.114, 0.159, 0.143 (OD450).

COVID-19 Patients:
Blank Control: 0.076 (OD450).
Serum From COVID-19 Patients: 0.11, 0.625, 6.082, 0.673, 0.568, 0.222, 0.234, 0.142, 1.166, 0.215, 2.222, 2.269, 0.438, 0.815, 1.279 (OD450).

It is advised that each laboratory establishes its own normal and pathological refence range for detection of anti-NP IgA antibodies.


– Inter Assay Precision: CV = Less than 10%.
– Intra Assay Precision: CV = Less than 8%.


  1. SARS-CoV-2 identification and IgA antibodies in saliva: One sample two tests approach for diagnosis. Clin Chim Acta. (2020) 510: 717-722. Aita A., et al.
  2. A comprehensive, longitudinal analysis of humoral responses specific to four recombinant antigens of SARS-CoV-2 in severe and non-severe COVID-19 patients. PLoS Pathog. (2020) 16 (9): e1008796. Chen Y., et al.
  3. Respiratory Mucosal Immunity: Kinetics of Secretory Immunoglobulin A in Sputum and Throat Swabs From COVID-19 Patients and Vaccine Recipients. Front Microbiol. (2022) 13: 782421. Ren C., et al.
  4. Accuracy of a nucleocapsid protein antigen rapid test in the diagnosis of SARS-CoV-2 infection. Clin Microbiol Infect. (2021) 27 (2): 289. e1-289.e4. Diao B, et al.


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