NAB-Sure™
Cell-free Neutralizing Antibodies Test Kits
(for research use only)
NAB-Sure SARS-CoV-2 Assay quantifies SARS-CoV-2 virus neutralizing antibodies using qPCR readout.
NAB-Sure SARS CoV-2 Kit simplifies testing from sample collection through result by using real-time PCR systems to produce qualitative and quantitative NAb (titer) measurements. It combines PRNT level accuracy with unparalleled sensitivity to assess small sample volumes including dried blood spot(DBS).
NAB-Sure is a surrogate virus neutralization test. It is a competitive binding assay that measures the ability of antibodies in a sample to block the SARS-CoV-2 Spike Protein from binding to the ACE2 receptor of a human cell. It is a homogenous immunoassay with no separation or wash steps.
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What is the principle of the NAB-Sure™ SARS-CoV-2 assay?
The NAB-Sure™ SARS-CoV-2 assay is a competitive binding assay that uses SPEAR technology. It is a surrogate virus neutralization test (sVNT), which measures the ability of antibodies in a sample to block SARS-CoV-2 Spike Protein from binding to the ACE2 receptor protein in solution. The assay is accurate, highly sensitive, and compares favorably with existing neutralizing antibodies assays.
What are neutralizing antibody assays for SARS-CoV-2?
Neutralizing antibody assays specifically detect and measure antibodies that block SARS-CoV-2 virus from entering host cells. Existing methods to detect these antibodies include cell-based assays and ELISA-based surrogate virus neutralization assays. Cell-based assays include plaque reduction neutralization test (PRNT), microneutralization assay (MNA), and pseudovirus neutralization assay (PVNA).
How is the NAB-Sure™ SARS CoV-2 assay different from other antibody tests?
NAB-Sure™ SARS-CoV-2 Assay is specific to neutralizing antibodies as opposed to total antibodies, including binding antibodies. In contrast, traditional ELISA and EIA immunoassays detect total antibodies against either SARS- CoV-2, the SARS-CoV-2 Spike Protein S1 subunit, or the Receptor Binding Domain (RBD) on S1.
Compared to ELISA-based surrogate virus neutralization assays, NAB-Sure™ SARS-CoV-2 Assay has a higher sensitivity to reliably detect neutralizing antibodies from smaller sample sizes (1 µL).
In addition, NAB-Sure™ SARS-CoV-2 Assay has many advantages over cell-based neutralizing antibody assays. For example, cell-based assays usually take 3-4 days, have high inter-lab variations, and require higher Bio Safety Level (BSL) laboratories.
How long does this test take to run?
This test takes approximately 6 hours if using plasma or serum samples. It will add 1.5 additional hours for sample processing if dried blood spot (DBS) samples are used.
Does this test indicate active infection?
This test does NOT detect the SARS-CoV-2 virus. It should not be used to determine active infection.
What sample types does the NAB-Sure™ SARS-CoV-2 assay support?
NAB-Sure™ SARS-CoV-2 assay has been validated with Dried Blood Spot (DBS), plasma, and serum samples.
What test result does this test produce?
NAB-Sure™ SARS-CoV-2 Assay is a surrogate virus neutralization assay, and it produces a neutralization curve for each sample with 6 data points. The neutralization titers are expressed as NT50, which refers to the sample dilution fold at which 50% of the interaction between S1 protein and ACE2 receptor is inhibited.
What are the sample requirements?
DBS samples need to be properly collected and dried before shipment with desiccant. Once received, DBS samples should be stored at -20°C or less until use. Plasma and serum samples need to be properly collected and stored at -20°C or less until use.
What is the lowest neutralizing antibody activity in WHO International Units per milliliter (IU/mL) that NAB-Sure™ SARS-CoV-2 Assay can detect and quantify NT50?
4.5 IU/mL for the wild-type SARS-CoV-2
Which systems are compatible with the NAB-Sure™ SARS-CoV-2 assay?
NAB-Sure™ SARS-CoV-2 Kit is designed to work with standard thermocycler and qPCR systems for 96 and 384 well plates. The assay has been validated with both manual and Integra liquid handling automation systems. Please see the NAB-Sure™ datasheet for more information on specific systems used in development.