The COVID-19 Surveillance Test Kit utilizes a No Template Control (NTC) to prevent false positive results due to contamination in consumables, in Common Mix solution, and/or between PCR tubes.
The No Template Control (NTC) is pure DNase, RNase-free distilled water and does not contain either SARS-CoV-2 or endogenous control target sequences. If there is any amplification of either of these targets, the experiment results will be Invalid and the saliva specimens should be rerun.
An Invalid result in the NTC indicates contamination. This could be cross contamination from the Positive Control tube or positive sample tubes, which can be prevented by minimizing the amount of time the Positive Control is exposed and working in a still air environment or biosafety hood. Prepare the PCR tubes in the right order (first saliva samples, then the NTC, and lastly the Positive Control).
Contamination can also come from surfaces, equipment or consumables. Wipe down all surfaces and equipment with aqueous detergents and wear all necessary personal protective equipment (PPE) prior to performing any portion of the kit workflow. Avoid talking, singing, coughing, or sneezing in the direction of the working surface. Make sure pipette tips are clean and not touched by hand. Change pipette tips between each solution and avoid contact with any unwanted surfaces. Prior to running the experiment, clean surfaces and instruments with aqueous detergents, use proper personal protective equipment (PPE), and work in a still air environment.