Question

While testing saliva for the presence of the coronavirus a technician notices that all of the samples came back positive. The test uses PCR. How should the test be modified to determine if the 100% positive is correct? (please explain in detail)

Answer 1

PCR = Polymerase chain reaction
It utilizes specific primers to amplify target nucleic acid sequences.

In the given case, 100% of the samples were tested positive for the Corona virus infection. It can be a true result or it is due to several other reasons.
PCR can give false positive results due to several reasons.
i. Sample contamination: The samples might have gotten mixed up during the procedure
Modification: Label everything properly and do the reaction sequentially.
Ensure that all the reaction components are pure.

ii. Primers are exhibiting non-specific binding
Modification: Perform PCr at increased annealing temperature