Human SARS-CoV-2 N IgG Antibody ELISA Kit

Code CSB-EL3325HU
Size 96T,5×96T,10×96T
Trial Size 24T ELISA Kit Trial Size (Only USD$150/ kit)
* The sample kit cost can be deducted from your subsequent orders of 96T full size kits of the same analyte at 1/5 per kit, until depleted in 6 months. Apply now
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Product Details

Alternative Names
N; Nucleoprotein; N; Nucleocapsid protein; NC; Protein N
SARS-CoV-2 N Ab (IgG)
Uniprot No.
Homo sapiens (Human)
Sample Types
serum, plasma
Assay Time
Sample Volume
Detection Wavelength
450 nm
Research Area
Infectious Diseases
Assay Principle

This assay mechanism is based on the qualitative enzyme immunoassay technique. The microtiter plate has been pre-coated with human SARS-CoV-2 nucleoprotein. Samples are pipetted into the wells with anti-human IgG conjugated HRP. Following a thorough wash, the TMB Substrate solution is added to the wells, eliciting a color change. The color develops in proportion to the amount of human SARS-CoV-2 N IgG antibody bound in the initial step. The addition of the stop solution to the wells terminates the color reaction. The color intensity can be measured at 450 nm via a microplate reader. The SARS-CoV-2 N IgG antibody titer in the samples is determined by referring to the negative control. It indicates the presence of SARS-CoV-2 N IgG antibody if the sample O.D. (optical density) is greater than or equal to the cutoff value (2.1×Average O.D. value of negative control). There is no SARS-CoV-2 N IgG antibody present in the sample if the O.D. is less than the cutoff value.
Intra-assay Precision (Precision within an assay): CV%<15%  
Three samples of known concentration were tested twenty times on one plate to assess.
Inter-assay Precision (Precision between assays): CV%<15%  
Three samples of known concentration were tested in twenty assays to assess.
Typical Data
Test parameter specification test result
Positive control ≥0.6 0.867
Negative control ≤0.25 0.184
Positive rate 20,Positive 100%
Negative rate 20,Negative 100%
Materials provided
    • A 96-well Coated assay plate --This microplate has been pre-coated with human SARS-CoV-2 nucleoprotein.
    • Negative Control (1 x 800 μl) --It is free of the SARS-CoV-2 N IgG antibody and used to preclude the false positive.
    • Positive Control (1 x 800 μl) --Used to evaluate the validity, stability, and comparability of the test results.
    • HRP-conjugated anti-Human IgG antibody (100 x concentrate) (1 x 120 μl) --Act as the detection antibody.
    • HRP-conjugate Diluent (1 x 20 ml) --Dilute the HRP-conjugated anti-Human IgG antibody.
    • Sample Diluent (2 x 20 ml) --Dilute the sample solution.
    • Wash Buffer (25 x concentrate) (1 x 20 ml) --Wash the unbound reagents.
    • TMB Substrate (1 x 10 ml) --React with HRP, eliciting a chromogenic color reaction.
    • Stop Solution (1 x 10 ml) --Stop the color reaction. The solution turns from blue to yellow.
    • Four Adhesive Strips (For 96 wells) --Seal the microplate when incubation.
    • An Instruction manual
Materials not provided
    • A microplate reader capable of measuring absorbance at 450 nm, with the correction wavelength set at 540 nm or 570 nm.
    • An incubator that can provide stable incubation conditions up to 37°C±5°C.
    • Centrifuge
    • Vortex
    • Squirt bottle, manifold dispenser, or automated microplate washer.
    • Absorbent paper for blotting the microtiter plate.
    • 50-300ul multi-channel micropipette
    • 100ml and 500ml graduated cylinders.
    • Deionized or distilled water.
    • Pipette tips
    • Timer
    • Test tubes for dilution.
and FAQs
Store at 2-8°C. Please refer to protocol.
Lead Time
3-5 working days after you place the order, and it takes another 3-5 days for delivery via DHL or FedEx

CUSABIO's Human SARS-CoV-2 nucleoprotein (N) IgG Antibody ELISA Kit allows for in vitro qualitative detection of the IgG antibody-specific for SARS-CoV-2 N protein in human serum and plasma. This research-use only kit can be applied in the studies associated with COVID-19, infectious and severe pneumonia caused by SARS-CoV-2. It has been validated with high sensitivity, high specificity, and high precision.

Nucleoprotein is the most abundant protein in SARS-CoV-2. It packs the positive-sense single-stranded viral RNA into a helical ribonucleocapsid (RNP), forming the viral nucleocapsid (N). The N protein plays an important role in improving the efficiency of virus transcription and assembly. It is also involved in viral pathogenesis. N protein possessing an immunogenic effect makes it trigger an immune response, which leads to the production of IgM/G against SARA-CoV-2 N protein. SARS-CoV-2 N IgG antibodies appear in the serum after 2-3 weeks after the onset of the symptoms, peaks within the third week, and gradually declines to a lower level. IgG-specific for SARS-CoV-2 N protein rapidly increases to a higher level after a secondary infection and retains in the body for several months even years.

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How do you use the Elisa kit using nucleoprotein or spike protein? Is there any difference in the recommended purpose fo usage?
Also, which do you recommend, IgG or IgM detection for CoVID-19?


Regarding ELISA kit for the detection of CoVID-19, we could only provide this item: CSB-EL3325HU, Human Novel Coronavirus Nucleoprotein (SARS-CoV-2 N) IgG Antibody ELISA Kit. It is only for research use, not for diagnostic purposes.
Usually, IgM is generated first in the primary immune response. IgM appears first in the process of virus infection, but it doesn't last long; IgG is the main antibody produced by the re-immune response, and it lasts for a long time. Generally, it indicates a past infection.

Target Background

(From Uniprot)
Packages the positive strand viral genome RNA into a helical ribonucleocapsid (RNP) and plays a fundamental role during virion assembly through its interactions with the viral genome and membrane protein M. Plays an important role in enhancing the efficiency of subgenomic viral RNA transcription as well as viral replication. May modulate transforming growth factor-beta signaling by binding host smad3.
Subcellular Location
Virion. Host cytoplasm.
Protein Families
Betacoronavirus nucleocapsid protein family
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