Wuhan coronavirus

There are several problems with mass testing. One is to have a suitable test method, one of the tests currently in use is known to be faulty. Second there is no such thing as an infallible test, even using the most advanced techniques they will probably only detect 95% of cases. Next is the production of adequate quantities of the test reagents, which is a hugely specialist task. Also tests have to be conducted by trained personnel, that means doctors or nurses or laboratory technicians or a combination, depending on the test type; the NHS is already stretched beyond capacity in many places. It is far more effective in epidemiological terms to target those at highest risk and their immediate contacts. BTW my first job was in immunology and microbiology.The diagnosis of COVID-19 must be confirmed by reverse-transcription polymerase chain reaction (RT-PCR) or gene sequencing for respiratory or blood specimens, this takes several days. First it involves tissue culture of the suspect material to produce enough virus for testing, this is tricky as sputum samples will be heavily contaminated with other organisms and these need to be controlled. The quickest testing I can imagine would be 3-4 days and possibly longer. Another method would possibly be immuno-fluorescence microscopy, I know this has been used as a research tool, but it is very labour intensive; I have seen images showing the techniques has been used. However I think that this latter is unlikely to be used as a field test.

https://www.worldometers.info/coronavirus/