Coronavirus Antibody Test - Animated Video

Summary

The video explains how the immune system responds to SARS-CoV-2 infection by producing antibodies, including IgM and IgG, which are detectable through a COVID-19 antibody test. It describes the test procedure, which involves using a cassette system to detect these antibodies in blood samples. The test uses gold nanoparticle conjugates for visual indicators and includes a quality control system. The results can indicate active or past infections, with positive or negative results based on the presence of IgM and IgG antibodies. However, test accuracy depends on antibody levels, and negative results may not rule out past infections.

Takeaways

• 😀 SARS-CoV-2 is the virus responsible for COVID-19, causing respiratory illness.
• 😀 The immune system produces antibodies (IgM and IgG) to fight the virus after exposure.
• 😀 IgM antibodies appear 4-7 days after symptoms develop, signaling early infection.
• 😀 IgG antibodies develop 7-14 days after symptoms onset and can persist for months or years.
• 😀 COVID-19 antibody tests detect IgM and IgG antibodies in blood, serum, or plasma samples.
• 😀 The test involves puncturing a finger, placing blood into a cassette, adding a buffer, and incubating for 10 minutes.
• 😀 The test is a lateral flow immunochromatographic assay with a cassette containing several components.
• 😀 Gold nanoparticles are used to label the virus antigen, allowing visual indicators through color changes.
• 😀 Three test lines on the cassette: anti-human IgM, anti-human IgG, and anti-rabbit IgG antibodies for quality control.
• 😀 A positive test shows both IgM and IgG, while a negative test indicates no detectable antibodies.
• 😀 If only IgM is positive, the immune system is producing antibodies to a recent infection.
• 😀 If IgG is positive and IgM is negative, the immune system has produced antibodies to an earlier infection.
• 😀 The test result can be invalid if the quality control line does not show a red color, requiring a retest.

Q & A

What is SARS-CoV-2 responsible for?

SARS-CoV-2 is responsible for causing Coronavirus Disease 2019 (COVID-19), a respiratory illness.

How does the immune system respond when exposed to a new virus?

When exposed to a new virus, the immune system creates proteins called antibodies as part of the body's natural response to fight the infection and neutralize the pathogen.

What are antibodies and how do they function?

Antibodies are proteins that the immune system produces to fight off infections. They can neutralize pathogens and can be present in different varieties, known as isotypes or classes, like IgM and IgG.

When are IgM antibodies typically detectable?

IgM antibodies are detectable in the early stages of infection, usually 4 to 7 days after symptoms develop.

How long after symptoms appear are IgG antibodies detectable?

IgG antibodies are typically detectable 7 to 14 days after symptoms appear and can remain detectable for months or even years, depending on the individual and the antigen.

What is the purpose of the COVID-19 antibody test?

The COVID-19 antibody test is used to detect the presence of anti-SARS-CoV-2 IgM and IgG antibodies in human blood, serum, or plasma samples.

How is the COVID-19 antibody test performed?

The test is performed by placing a test cassette on a level surface, puncturing a finger to collect blood, adding a drop into the cassette, and adding a buffer. The test is then incubated for 10 minutes.

What components are involved in the lateral flow immunochromatographic assay?

The test involves a sample pad, a conjugation pad with gold-labeled COVID-19 antigen, and a nitrocellulose membrane with three lines to detect IgM, IgG, and rabbit IgG antibodies.

What does the appearance of a colored line indicate in the test?

A colored line appears when the gold nanoparticles conjugated with the COVID-19 antigen bind to the IgM or IgG antibodies in the sample. The presence of lines indicates a positive result.

How do the test results vary based on the antibodies detected?

If both IgM and IgG antibodies are present, the result is positive for an ongoing infection. If only IgM is detected, it suggests a recent infection. If only IgG is detected, it indicates past infection. A negative result suggests no infection or an undetectable antibody level.