COVID Testing

PCR

• Polymerase Chain Reaction -
• Need a marker for $50, which can do 1000 tests
• Need a lab
• Nobel Prize of 1985 for PCR
• Good for gene synthesis -
• Virus has been sequenced -
• Primers - to be sequenced -
• 10k - base pairs
• What primer to select? There are regions of the genome that
• Influenza - virus. It's quite mutable
• Look at the sequence - it's random. Take a specific region.
• Unique to COVID - take a gene sequence.
• $100- for 100 or so tests
• PAPR

Controversy

• USA has very little testing, and as such, confirmed cases are underreported - [1]

Links

• Serum tests (antibody tests) can detect who HAD COVID - by presence of antibodies. RT-PCR detects only who currently HAS COVID. [2]
• Description of RT-PCR from Wired. Also mentions Crispr tech being used for quicker tests. - [3]
• COVID genomes - [4]
• COVID Test Kits
• 30 minute test - [5]. The tests consist of strips of paper that are coated with antibodies that bind to a specific viral protein. Isolate antibodies from patients. Sequence them, then make them synthetically. Antibody is a tag that attaches to protein. You detect the virus antibody - such as ELIZA Assay. Colorimetric assay. Suppose you want to detect virus. Take a sample. Add it to a multiwell dish. Coat dish with sample, add anitbody that would attach to it if there is one. Wash everything else, and and detect the antibody that attached. IGG type secondary antibody - which has a fluorescent tag. Which you can detect with a biochemical reaction. They don't have the sequence of the antibody yet. They are produced by T-Cells. Culture the cells, isolate antibodies from them. This difficulty was demonstrated with AIDS. It happens 3-4 months. Need 100 ml of blood sample. If it works well, you may succeed in getting the cells that produce antibodies. You expose them to virus, and they produce antibodies. Need to replicate T-Cells. It's not trivial. Requirements for cell to grow are finicky.
• PCR vs antibody testing - Why antibody testing will matter. And the fragility of global supply chains being in China. [6]
• Immunoassay - [7] - lateral flow automated immunoassay - [8]