Thread On tests and the media
It is almost universal that any piece discussing Rapid Ag tests says “PCR is more accurate but…”
But even this isn’t true. It simply depends what you want to detect.
If wanting to identify ppl who are contagious, PCR is much less accurate.
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It is almost universal that any piece discussing Rapid Ag tests says “PCR is more accurate but…”
But even this isn’t true. It simply depends what you want to detect.
If wanting to identify ppl who are contagious, PCR is much less accurate.
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If your goal is to detect ppl are infectious, a rapid Ag test is highly sensitive AND specific for this.
PCR is not specific for this. It will read positive even when not infectious. So… it’s less accurate for the public health question at hand “am I infectious”
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PCR is not specific for this. It will read positive even when not infectious. So… it’s less accurate for the public health question at hand “am I infectious”
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You might say… well PCR is much more sensitive. But even that is not true. A bit more, yes, but if wanting to catch infectious ppl, it’s really but that much more sensitive and, if that’s your goal, then PCR is massively LESS effective than a rapid test.
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An analogy:
If I want to ask “Is my leg bone broken in half”
Sure, an MRI is technically a more sensitive technology overall, but a fast X-ray is going to be essentially 100% sensitive for the question - “is my femur in 2 pieces”
The MRI slows w/out adding much
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If I want to ask “Is my leg bone broken in half”
Sure, an MRI is technically a more sensitive technology overall, but a fast X-ray is going to be essentially 100% sensitive for the question - “is my femur in 2 pieces”
The MRI slows w/out adding much
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The whole reason we’re in a mess of not having enough rapid tests today is bc confusion surrounding their utility in this pandemic.
So please, media, think about what it means when you say less accurate
It may be exactly the opposite - and in the case of rapid tests, it is
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So please, media, think about what it means when you say less accurate
It may be exactly the opposite - and in the case of rapid tests, it is
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I think general public may not be familiar with term "Specific" in terms of testing
For tests to identify infectious ppl, "Specific" means the test will only be positive when someone is currently infectious (not after). Rapid tests are "Specific" for this. lab PCR not so.
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For tests to identify infectious ppl, "Specific" means the test will only be positive when someone is currently infectious (not after). Rapid tests are "Specific" for this. lab PCR not so.
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