When a nucleic acid test is done, the swab is usually not coated with the drug.
When performing a nucleic acid test, the swab, or pharyngeal swab, is used to scrape off and take a small amount of body fluids and human cells, which are then placed into the test reagent in the test tube. If nucleic acids of the pathogen are present in the body fluids and cells, they will be detected during the test, which is a positive nucleic acid test. If the nucleic acids of the pathogen are not present in the body fluids and cells, the nucleic acid test is negative.
Therefore, no medication is applied to the swab when doing the nucleic acid, and the application of medication can interfere with the results of the test. When doing the nucleic acid test, it is recommended to fully expose the pharynx or nasal cavity, so that the swab of the nucleic acid test can fully rotate on the mucous membrane and scrape a valid specimen, which improves the correctness of the nucleic acid test, and reduces the possibility of false-positive and false-negative occurrences.