Application of the kit:

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The “SARS-CoV-2-IgG-ELISA”  reagent kit is designed for the qualitative detection of class G immunoglobulins for SARS-CoV-2 coronavirus in human serum or plasma and is recommended for in vitro diagnosis and epidemiological studies.

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Relevance of the problem:

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Widespread incidence of the new coronavirus infection COVID-19 caused by the SARS-CoV-2 virus has set complex tasks to the medical community, connected with a quick and reliable diagnostics and efficient treatment of the patients with this infection. The most dangerous complications associated with a high mortality rate among patients with COVID-19 who are monitored in intensive care units include acute respiratory distress syndrome (ARDS). The main role in the pathogenesis of ARDS is played by the excessive response of the immune system, as a result of which a systemic inflammatory response syndrome (cytokine storm) can develop.

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This specificity of viral disease presumes the production of antibodies to the components of viral particles. The detection of these antibodies confirms a past illness or asymptomatic carriage and indicates the presence of immunity. The duration and intensity of immunity to SARS-CoV-2 have not been studied well enough so far, so, in the event of a repeated threat of the disease, repeated studies can be carried out.

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Diagnostic methods for the new coronavirus infection COVID-19:

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Initially, SARS-CoV-2 infection can be confirmed by the detection of pathogen RNA in biological samples of the patient, such as bronchoalveolar lavage, sputum, oropharyngeal swabs. SARS-CoV-2 RNA can be diagnosed from the first days after infection and is a fairly sensitive study. Currently, these tests are widely used and represented by kits of both foreign and domestic production. The test systems of the PCR-RT and LAMP format (loop isothermal amplification) are mainly used.

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The disadvantages of PCR-based diagnostics are that the persistence of the virus in the tissues is observed for a short time. According to the studies, 90% of the tests for SARS-CoV-2 viral RNA in nasopharyngeal swabs become negative 8-10 days after the onset of symptoms, and, thus PCR test systems can give false-negative results during a later period after infection. Besides, false-negative PCR test results can be obtained with an asymptomatic course of the disease in a patient. Serological research methods based on the diagnosis of specific antibodies (immunoglobulins) to the SARS-CoV-2 virus are devoid of these drawbacks. Methods for detection of serum antibodies include colloidal gold immunochromatography, ELISA, chemiluminescent immunoassay, etc. Specific IgG antibodies appear in the blood of patients with SARS-CoV-2 already 12 days after the onset of the symptoms and can be detected for a long time, while the titer of specific IgG antibodies in the recovery phase is about 4 times higher than in the acute phase. Positive specific IgG can be used as a diagnostic criterion in patients with suspected COVID-19 with a negative nucleic acid test, to detect asymptomatic and obliterated/supressed forms of COVID-19, to determine the duration and intensity of immunity to SARS-CoV-2, as well as for identification of potential plasma donors that can be used in the treatment of severe forms of COVID-19.

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Assay principle:

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The “SARS-CoV-2-IgG-ELISA” reagent kit is a test system based on the method of indirect enzyme-linked immunosorbent assay. A recombinant SARS-CoV-2 virus antigen is applied to the bottom of the wells of a polystyrene collapsible / non-separable plate, which during the incubation process interacts with SARS-CoV-2 antibodies present in the test sample. Then, antibodies to human immunoglobulins of class G (IgG) labeled with the enzyme (horseradish peroxidase) are added to the formed immune complex. After performance of a substrate-enzymatic reaction with the participation of a chromogen (tetramethylbenzidine, TMB), the obtained results are recorded. If there are specific anti-SARS-CoV-2 class G immunoglobulins (IgG) in the sample, the optical density in the well exceeds the values of the negative control samples, and is proportional to the content of specific class G antibodies in the sample.

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Application field of the kit:

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The “SARS-CoV-2-IgG-ELISA” kit is intended for use in clinical laboratory diagnostics. The “SARS-CoV-2-IgG-ELISA” kit is used to detect a specific class G immunoglobulins (IgG) for the SARS-CoV-2 coronavirus in all individuals without gender essional use only. Only for diagnostics in vitro. For medical organizations irrespective of their legal status.

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General description of the kit:

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Full name:"Detection kit for class G immunoglobulins (IgG) to coronavirus SARS-CoV-2 by immuno-enzyme method"

Brief name: SARS-CoV-2-IgG-ELISA

Shelf life of the kit: 1 year

Detection range Qualitative: positive and negative control

Control samples: 2 (are included in the kit)

Total assay time: Not more than 120 minutes

Assay scheme: Two stages

Volume of biological material for the assay (blood serum/plasma): 10 mcl

Number of detections: The kit is designed for 96 detections including controls. For manual and automatic methods

Preparedness of the kit components for use: Preliminary preparation of the working solution of the wash buffer (WB). The other components are to use.