Anti-SARS-CoV-2 Neutralization Antibody Test Kit (Colloidal Gold) (A269980)

The Anti-SARS-CoV-2 Neutralization Antibody Test Kit (Colloidal Gold) is a rapid in vitro chromatographic immunoassay, used for the qualitative detection of neutralization antibodies against SARS-CoV-2 viral spike proteins, in human whole blood, serum or plasma samples. The coronaviruses encode four major structural proteins, the spike (S), membrane (M), envelope (E), and nucleocapsid (N) proteins. The S protein contains a receptor-binding domain (RBD), which is responsible for recognizing and interacting with the cell surface receptor angiotensin-converting enzyme 2 (ACE2). ACE2 is widely expressed in the respiratory tract of the lungs, on the cell surfaces in the alveoli, trachea, and bronchi, as well as on macrophages and other cell types. The ACE2-RBD interaction is essential for SARS-CoV-2 virus particle entry into the host cells, and therefore viral replication and infection. Neutralizing antibodies secreted by B lymphocytes can bind to the RBD, blocking the interaction with ACE2, and granting the host strong immunity against the pathogen.

The test is a qualitative membrane-based immunoassay for the detection of SARS-CoV-2 neutralizing antibodies. The blood sample and a buffer solution are dropped into the sample well, and the solution migrates up the membrane by the capillary effect. If there are neutralizing antibodies in the sample, these bind to colloidal gold-labeled SARS-CoV-2 spike protein (S) contained within the membrane, and these travel up the membrane with the solution. Once the solution reaches the test (T) line, the spike protein subunit RBD-NTD-CTD that is coated to the T area is also bound by the neutralizing antibodies. The coated spike protein-neutralizing antibody-spike protein-colloidal gold complex at the T area becomes visible as a colored line, as the colloidal gold appears red when concentrated. If there are no neutralizing antibodies in the sample, the colloidal gold labelled spike proteins spread over the membrane instead, and no red line appears at the T area.

The solution also contains colloidal-gold labeled chicken IgY, which is captured by mouse anti-chicken IgY antibodies coated to the membrane at the control (C) line. If the C line does not appear after 15 minutes, the result is invalid, and the sample needs to be tested again using a new test cassette, carefully following the instructions. The C line appearing indicates the buffer solution has been applied, proper membrane wicking has occurred, and antibodies are able to bind in the test conditions. The absence of a C line helps to identify false negative test results.

Anti-SARS-CoV-2 Neutralization Antibody Test Kit (Colloidal Gold) comes in packs of 25 tests and contains:

• 25 x Test Cassette.
• 1 x Buffer Bottle
• 25 x Dropper

Clinical performance:

The performance of this kit was established using 626 clinical samples, with results compared to those from a plaque reduction neutralization test (111 positive, 515 negative). The kit displayed a sensitivity of 98.2% (109/111), and a specificity of 99.2% (511/515). Please refer to the datasheet for additional performance statistics.

Hook Effect:

The Hook effect is an immunological phenomenon in which the ability of antibodies to form immune complexes is sometimes impaired when concentrations of an antibody or an antigen are very high, resulting in false negatives or inaccurately low results. There was no hook effect observed within the titer range of positive samples.

Cross-reactivity:

There was no cross-reactivity observed with antibody/antigen positive sera samples from patients with other human coronaviruses (HCoV-HKU1, HCoV-OC43, HCoV-NL63, HCoV-229E), or non-coronaviruses, including influenza A virus (H1N1, H3N2, H5N1, H7N9), influenza B virus (Yamagata and Victoria lineages), respiratory syncytial virus, rhinovirus, adenovirus, enterovirus, Epstein-Barr virus, measles virus, human cytomegalovirus, rotavirus, norovirus, mumps virus, herpes zoster virus, or Mycoplasma pneumoniae.

Warnings:

• For in vitro diagnostic use only.
• For medical professional use only.
• Do not reuse any test components.
• Handle all samples cautiously as if they contain infectious agents. Observe established precautions against microbiological hazards throughout the procedure and follow the standard procedures for proper disposal of samples.
• Wear protective clothing such as laboratory coats, disposable gloves, and eye protection when samples are being assayed.
• The used tests, samples, and potentially contaminated items should be discarded according to the local regulation.
• Unreasonable sampling, transportation and handling, or low virus content in the sample will lead to false negative results. Humidity and temperature can adversely affect results.
• Anti-SARS-CoV-2 Neutralization Antibody Test Kit will only indicate the presence of SARS-CoV-2 neutralization antibodies in the sample and should not be used as the sole basis for determining immune status, and should be combined with other test methods, such as live virus and pseudovirus neutralizing antibody assays.