Nucleic acid test will be false positive if the specimen is contaminated, PCR reagent is contaminated, PCR amplification product is contaminated, aerosol is contaminated and cloned plasmid is contaminated in the laboratory.
1. Specimen contamination: If there is contamination in the process of collecting samples, for example, the containers are not sealed tightly and the virus leakage will lead to cross-infection between the containers.
2. PCR reagent contamination: PCR (polymerase chain reaction) may be contaminated by the spiking gun, double-distilled water and containers in the process of preparation.
3. PCR amplification product contamination: this is more common, if the copy amount of the PCT product exceeds 1013copy/mL, it may be contaminated.
4. Aerosol contamination: Aerosol contamination may occur when professionals repeatedly aspirate samples as well as open the cap.
5. Clonal plasmid contamination in the laboratory: this situation is purified by the appliances needed as well as more reagents, and the plasmid in the living cell, the living cell reproduction speed is relatively fast, easy to produce contamination.
If there is a positive result in the nucleic acid test, it is recommended to undergo re-testing to clarify the diagnosis.