Why can't corona testing be done in bulk?

Question

I have often wondered why it isn't possible to combine swabs from large numbers of people and PCR the soup to check for the presence of a virus. In the best case, one can eliminate large numbers (dorms, hospital janitorial and nursing staff) at one shot, and makes frequent (daily) testing possible for people at risk). If the sample tests positive, then perhaps (perhaps..) it is possible to figure out the affected subset in a log number of further tests. Am I missing something?

rolph · Accepted Answer

more samples together increases offchance of crossover contamination producing a false indication.
under the assumption that a corona virus case displays symptoms around day 5 it doesnt make any sense to test if the results come through at the same time as symptoms would arise in positive case.
in my area there is a claim of 3 days shipping of a sample before tests are performed and results submitted.
if you have a lot of samples, abunch of 96 , and 48 well sample trays then bulk testing is efficient if you are careful. If you have to wait, to accumulate samples for a batch, that is not soon enough.