Dr Mark Porter (via Twitter):
Testing thread: most of you know this, but for those who are not sure. There are 2 types of Covid test in common use:
1. PCR swabs (nose & throat) detect viral genetic material. They can pick up low levels of the virus & are very accurate at confirming, and excluding, infection.
2. Rapid antigen tests (lateral flow like Innova) look for protein from the surface of the coronavirus. They are good at detecting high concentrations (when the person is likely to be most infectious) but miss many people with lower levels (a false negative rate of 25% or more).
3. A PCR swab is generally done in a specialist testing centre / hospital and the result takes hours/days to come back. The rapid antigen lateral flow can be done anywhere, by anyone and gives a result in minutes.
4. If you have symptoms you MUST have a PCR test to exclude Covid. Do NOT use a lateral flow test to rule it out as they are not accurate enough. If you have a positive lateral flow test then self isolate until you have the result of a proper PCR test.
Testing thread: most of you know this, but for those who are not sure. There are 2 types of Covid test in common use:
1. PCR swabs (nose & throat) detect viral genetic material. They can pick up low levels of the virus & are very accurate at confirming, and excluding, infection.— Dr Mark Porter (@drmarkporter) June 30, 2021