Test Code (รหัสการทดสอบ):
Order Name (ชื่อการทดสอบ):
SARS-CoV-2 (COVID-19) Neutralizing Antibody
Clinical Information (ข้อมูลทางคลินิก):
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belongs to the family of coronaviruses and, like SARS-CoV, is classified in the genus Betacoronavirus. At the end of 2019, SARS-CoV-2 was identified as the causative pathogen of clustered cases of pneumonia of unclear origin. The virus caused an infection wave that has spread rapidly worldwide and was declared a pandemic by the WHO at the beginning of 2020.
The determination of antibodies enables confirmation of SARS-CoV-2 infection in patients with typical symptoms and in suspected cases. It also contributes to monitoring and outbreak control. The spike (S) and nucleocapsid (N) proteins of SARS-CoV-2 are highly immunogenic. To enter and thus infect new cells, the virus binds to the ACE2 receptor of the host cells using the receptor binding domain (RBD) of the spike protein. The RBD is the target antigen of over 90 % of the neutralising antibodies in COVID-19 patients. Neutralising antibodies are associated with protective immunity against a second infection with SARS-CoV-2. The spike protein is therefore the target protein of almost all COVID-19 vaccines. Around 90 % of SARS-CoV-2 patients develop specific antibodies up to day 10 after symptom onset. IgG, IgA and IgM against the spike protein often appear at the same time.
For significant serological results, two patient samples should be investigated, one from the acute phase (week 1 of the illness) and one from the convalescent phase (3 to 4 weeks later).
% Inhibition >= 35 = Positive, the results suggest prior infection with SARS-CoV-2 or vaccination against SARS-CoV-2. Measurement of the neutralising activity of anti-S1/RBD antibodies enables confirmation of their functionality in inhibiting binding of S1/RBD to ACE2.
% Inhibition <20 = Negative, the results may occur in samples collected too soon following infection or immunization, or in immunocompromised patients. In cases of recent SARS-CoV-2 infection or vaccination, re-testing is recommended after 14 days.
% Inhibition >= 20 to < 35 = Borderline, the presence or absence of neutralizing antibodies cannot be concluded. Borderline samples have either very low antibody titers or are negative for antibodies that neutralize SARS-CoV-2. Re-testing recommended after 14 days.
Negative results do not rule out SARS-CoV-2 infection, the results should always be interpreted together with those of further laboratory diagnostic procedures and based on the clinical picture.
The test results should not be used to diagnose acute SARS-CoV-2 infection. Antibody tests can identify persons with resolving or past SARS-CoV-2 infection.
Clinical Reference (เอกสารอ้างอิง):
Manufacturer’s reagent package insert, SARS-CoV-2 NeutraLISA instruction, August 2021, EUROIMMUN, Lübeck, D-23560 Germany.