Name: Coronavirus Antibody Test - Animated Video
Uploaded: 2022-11-22T13:27:12.000Z
Duration: 5 min 1 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

The SARS-CoV-2 is an emerging virus responsible for the respiratory illness Coronavirus Disease 2019

the immune system creates proteins called antibodies

as part of the body’s natural response to fight the infection and to neutralize the pathogen

Antibodies can come in different varieties known as isotypes or classes

IgM antibodies are produced against the viral antigen in the early stages of infection

and are detectable after four to seven days after symptoms develop

Following that, IgG antibodies are produced seven to 14 days after the onset of symptoms

and are detectable for months and even years

depending upon the antigen and the individual

These antibodies can also be detected if a person has an infection without any symptoms

The COVID-19 antibody test is used to detect the presence of the anti-SARS-CoV-2 IgM and IgG antibodies

in human whole blood, serum, or plasma samples

To perform a test, the cassette is placed on a level surface at room temperature

then one of the fingers is punctured with a lancet

and a plastic dropper is used to take several drops of blood

then one drop is added into the cassette sample well

Finally, drops of a buffer are added into the sample well to facilitate the test

and the cassette is incubated for 10 minutes

The test Kit is a qualitative lateral flow immunochromatographic assay

a sample pad, where the combined sample flows down

A conjugation pad, which contains Gold - Covid-19 antigen conjugate

the antigen will bind to the anti-SARS-CoV-2 antibodies in the sample

one with affinity to IgM and a second with affinity to IgG antibodies

The virus antigen is labelled with gold nanoparticles

because of the nanoparticle’s interactions with visible light

So that, the Gold nanoparticles absorb and scatter light

In addition, rabbit IgG antibodies labeled with gold nanoparticles exist in the conjugation pad

and they are used for quality control to assess test validity

the test strip also contains a nitrocellulose membrane with three lines

first line coated with anti-human IgM antibodies

second line coated with anti-human IgG antibodies

and third line coated with Anti-Rabbit IgG Antibodies

In addition, an absorption pad is used in the test strip to move the sample across the test

The sample migrates laterally across the membrane by capillary action.

During testing, the antibodies in the sample

react with the SARS-CoV-2 antigen, and its conjugate gold nanoparticles

The mixture then migrates laterally across the membrane by capillary action

to the anti-human IgM and anti-human IgG antibodies, respectively

While, the rabbit IgG antibodies are bound to the Anti-Rabbit IgG Antibodies

Only those conjugated with COVID-19 antigen-gold nanoparticle complexes

if both IgM and IgG antibodies are detected

the subject’s immune system is actively producing antibodies

to a recent infection with the target virus

to an ongoing infection that likely began more than 14 days ago

the subject’s immune system has produced antibodies to the target viral antigen

A negative test result means that the person is not infected with the virus

or perhaps the person has a recent infection but the antibodies are not yet produced

Also, since the accuracy of the test depends on the amount of the antibodies

some people may not develop detectable antibodies after an infection

we don’t know exactly how long antibodies last

so a negative test could mean that the person has been infected in the past

and the antibodies are no longer detectable

if the quality control line C does not show a red color

Subtitles ListPlay Video

Coronavirus Antibody Test - Animated Video

immune

present

positive

presence