Part of my job involves work in the ICU. It hasn’t hit my region of the country bad, yet, but it is spreading and the situation in Italy and what is developing in New York is what myself and all my colleagues dread being faced with.
The PCR swans are what is being utilized primarily. The specificity is hard to say since we aren’t doing viral culture or have another “gold standard” to compare to, but is probably excellent. The sensitivity, however, does seem to be much worse and may be as low as 70%. Seems that the method of obtaining does play a role as well.
For any confused on sensitivity/specificity, sensitivity is basically “if someone has the disease, the likelihood the test will detect it” meaning false negatives lower it. Specificity is “if someone doesn’t have the disease, the likelihood the test will be negative” meaning false positives will lower it.
In the context of COVID-19, this means we are seeing a fair amount of false negatives via the swab and probably not seeing very many false positives.
(03-27-2020, 05:35 AM)Jannemann2 Wrote: There's testing and testing.
I think the PCR based tests (detecting virus RNA) which are the main tests used up to now are quiet good (highly sensitive, highly specific), but I hear the number of viruses in the throat is heavily reduced while the disease proceeds (even in bad cases) because the main activity of the virus travels down into the lungs. So the probes for testing need to be taken the right way.
The PCR swans are what is being utilized primarily. The specificity is hard to say since we aren’t doing viral culture or have another “gold standard” to compare to, but is probably excellent. The sensitivity, however, does seem to be much worse and may be as low as 70%. Seems that the method of obtaining does play a role as well.
For any confused on sensitivity/specificity, sensitivity is basically “if someone has the disease, the likelihood the test will detect it” meaning false negatives lower it. Specificity is “if someone doesn’t have the disease, the likelihood the test will be negative” meaning false positives will lower it.
In the context of COVID-19, this means we are seeing a fair amount of false negatives via the swab and probably not seeing very many false positives.