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


SARS-CoV-2 was a worldwide disease that was found to spread rapidly during 2019, it caused a massive treat posed a global health and safety. The four structural proteins that make up this virus—NP (nucleocapsid), M (membrane), E (envelope), and S (spike)—can each live and replicate on their own. Chest pain, a cough, a high temperature, and shortness of breath are classic signs of SARS-CoV-2. Muscle aches, malaise (a sensation of unease), headaches, and weariness are possible additional symptoms. of SARS-CoV-2. A tiny number of changes that changed the length and function of the virus caused the SARS-CoV-2 genome to be 100% similar to the SARS virus’s sequence. The two were regarded as recombinants since they originated from two different coronavirus strains, one from bats and one from humans. SARS viruses are classified as coronaviruses which are single stranded RNA viruses with 7 segments (A, 5′ untranslated region; B, 3′ untranslated region; C1, caps id protein 1; C2, capsid protein 2; D, membrane fusion domain; E2a and E2b, spike glycoproteins).The SARS-CoV-1 genome is 100% identical to the human coronavirus HKU4. It has been been documented as a strain of a coronavirus that has appeared in humans thus far.

The nucleocapsid protein has an important role in associating with the viral RNA to generate a helical ribonucleoprotein complex. The NP can also form links with the positive stranded RNA genome and the M protein, this is vital for the process of virus replication. From the four proteins, the nucleocapsid is the most abundant protein that is found in the coronavirus. The M protein is the smallest member of the virus particle. It is composed of a globular head that includes a lipid-binding domain and three fibrous tails. The protein facilitates membrane fusion and differentiates between enveloped and non-enveloped virions during virus entry into host cells.


Human SARS-CoV-2 NP IgM ELISA kit is designed for detecting IgM class of antibodies to nucleocapsid protein (NP) of the SARS-CoV-2 virus using samples of human plasma and serum samples.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • SARS-Co-V-2 NP Coated ELISA Plate.
  • 5x Assay Buffer.
  • 10x Wash Buffer.
  • 100x Detection Antibody Buffer.
  • Substrate Solution.
  • Stop Solution.
  • Blank Control.
  • Positive Control.


Negative Control: 0.113, 0.098, 0.121 (OD450).
Positive Control: 0.531, 0.568 (OD450).
Serum From Healthy Subjects: 0.127, 0.154, 0.097 (OD450).
Serum From COVID-19 Patients: 1.052, 0.38, 0.242 (OD450).

Suggested Cut-Off Values:
Negative: < 0.20 (450nm).
Positive: ≥ 0.20 (450nm).

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


– Negative Result: Samples absorbance/cut-off < 0.9.
– Positive Result: Samples absorbance/cut-off > 1.1.
– Borderline Result: Samples absorbance/cut-off = 0.9 – 1.1.
– Detection Rate: 88.64%.
– Specificity: 96.31%.
– Inter Assay Precision: CV% 7.16, 5.35, 6.19.
– Intra Assay Precision: CV% 4.93, 6.77, 5.89.


  1. Rapid Detection of IgM Antibodies against the SARS-CoV-2 Virus via Colloidal Gold Nanoparticle-Based Lateral-Flow Assay. ACS Omega. (2020) 5 (21): 12550-12556. Huang C, et al.
  2. The T-cell independent antigen, NP-ficoll, primes for a high affinity IgM anti-NP response. Mol Immunol. (1988) 25 (12): 1277-82. Maizels N, et al.
  3. Rapid decline of neutralizing antibodies is associated with decay of IgM in adults recovered from mild COVID-19. Cell Rep Med. (2021) 2 (4): 100253. Harrington W.E., et al.
  4. SARS-CoV-2 serology and virology trends in donors and recipients of convalescent plasma. Dulipsingh L., et al. Transfus Apher Sci. (2020) 59 (6): 102922.


Online Enquiry Form

"*" indicates required fields

Please check mark information required:


Your secretory IgA ELISA gave good results and I was also really impressed with how quickly we received it.

L. Johnston
PhD Student / University of Glasgow

It is refreshing to know that you have a technical team that is very knowledgeable. I have already recommended your company to other researchers in our department.

Dr. P. Anderson
Lecturer / University College London (UCL)

I am a first time user and found that your instruction manual was very easy to follow. The insulin ELISA assay performed well and I was happy with the results that were generated.

J. Thomas
Senior Technician / Addenbrooke’s Hospital

I carried out a pilot study comparing the performance of many ELISA assay's from different suppliers and found your kits to be one of the better performers. We observed good linearity and tight replicates.

Dr. C. Davies
Lead Scientists / AstraZeneca

You are my first point of contact when I am looking to purchase ELISA. You have such an easy and simple system, yet it is very effective.

A. Shaw
Purchasing / University of Oxford