How to test someone for COVID-19
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Fluorescent probe
RT-PCR machine
Lysis buffer
A test for COVID-19 starts with a sample. Usually, this is done with a swab that goes deep in a person’s nose and throat. It is then placed in about ½ tsp. of fluid.
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Glowing
coronavirus
Swab
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Lab scientists combine small amounts
of a person’s sample with a lysis buffer,
a chemical which breaks open the person’s (potentially) virus-infected cells, so that
viral RNA can be extracted. RNA carries
the coronavirus' genes in the same way
DNA carries human genes.
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How to test someone for COVID-19
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Lysis buffer
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RT-PCR machine
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Fluorescent probe
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coronavirus
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Swab
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Swab
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Lysis buffer
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RT-PCR machine
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Fluorescent probe
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How to test someone for COVID-19
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How to test someone for COVID-19
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Lysis buffer
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RT-PCR machine
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Fluorescent probe
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All the viral RNA inside the tubes is then amplified, inside a RT-PCR machine. The machine makes many copies of the genetic material to see if the coronavirus is present.
Swab
How to test someone for COVID-19
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Swab
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Lysis buffer
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RT-PCR machine
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Fluorescent probe
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coronavirus
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A special fluorescent probe for each gene
in the coronavirus that the scientists want
to target is added to the tests.
Probe
Target gene
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How to test someone for COVID-19
Each probe is on a mission to find its specific target gene, but most COVID-19 tests use
more than one probe, targeting multiple coronavirus genes.
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Lysis buffer
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Swab
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Swab
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Lysis buffer
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RT-PCR machine
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Fluorescent probe
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coronavirus
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How to test someone for COVID-19
If the coronavirus gene that the probe is looking for is present in the sample, the
RT-PCR amplification process will turn
on the probe’s fluorescent lights. As more coronavirus genes get amplified over time, the fluorescent lights in the test probes
will glow brighter and brighter.
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Swab
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Lysis buffer
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RT-PCR machine
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Fluorescent probe
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Glowing
coronavirus
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Results
How to test someone for COVID-19
Tap each step to learn more
1
Swab
2
Lysis buffer
3
RT-PCR machine
4
Fluorescent probe
5
Glowing
coronavirus
6
Results
How to test someone for COVID-19
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BACK
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How to test someone for COVID-19
The amplification happens inside the
RT-PCR machine, where lab workers
can’t physically see whether the probes are glowing. Instead, the machine records spikes on a data graph that track the glowing as it gets brighter and brighter, revealing when a patient has COVID-19. Negative results won’t show the spikes.
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Lysis buffer
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RT-PCR machine
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Fluorescent probe
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Glowing
coronavirus
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Results
Swab
How to test someone for COVID-19
Tap each step to learn more
1
Swab
2
Lysis buffer
3
RT-PCR machine
4
Fluorescent probe
5
Glowing
coronavirus
6
Results