This is what I cant understand.
I think there must be a cheap, *smile*, innacurate, slow test
and an expensive, good, fast, accurate test???
What I dont get is If I want to go to WA, I pay $3000 to quarantine for 14 days. Surely I could pay that $3000 for the best Covid test available, wait 24 hours for a negative (im pretty sure some give an almost instant result), and carry on?
surely the good test isnt more expensive than 14 day rooms and board and 3 *smile* tests?
I know for a fact, that mining companies are conducting fast, accurate tests on their FIFO workers
If well managed,
means majority of your citizens who return with international Covid,
spend 14 days locked up 4000km away,
then, yes, I agree WA is very well managed
In regards to how the tests work, there are actually a few different versions of tests, which can either assess one of three things.
Whether you have covid antigens in your system (the viral protein), whether you have covid genetic material in your system (the viral RNA - effectively its genome and information to make the protein) or whether you have antibodies against covid in your system (host proteins that fight off the virus).
They can be used to find out different stuff depending on what you're interested in.
The 'gold standard' that we're using for initial diagnosis is to see if the viral RNA is present.
To do this, you need to go through a few steps of purification/isolation on the patient sample, then go through a few rounds of PCR (amplification/copying of the RNA) to get it to high enough levels to visualise and see if it's really there.
Where these tests have gotten faster is in the purification/isolation steps (some omit them entirely) but that does sacrifice sensitivity slightly. Just as an aside, sensitivity is how likely you are to catch all the real positives (and lower the risk of false negatives) and accuracy is knowing that when you get a positive it actually is positive (and lower the chance of false positives).
Tests have also gotten faster by streamlining the lab tech work, employing more people, and batching more efficiently.
So faster doesn't mean better, it just means faster.
The real kicker here is that because you're looking for the test to pass a certain threshold (amount of RNA) rather than a binary yes/no, you can be infected, still show up negative, then once the viral genome has multiplied to high enough levels, you'll show up positive.
That's the logic behind the multiple tests. Like anything here though, its a social and political question how safe you play it. How many tests are enough? Three is always a good number in testing.
