What is Molecular Tests?

• Molecular tests amplify bits of viral RNA so that viral infection can be detected using a specialized test. These tests also are referred to as nucleic acid amplification tests (NAAT). The procedure begins by taking a sample from a potentially infected person’s nose or mouth (saliva), where virus might be found. If SARS-CoV-2 is present in the sample, then even low levels of virus genomic material can be amplified into millions of copies detected during a molecular diagnostic assay.

• If a person is infected, the viral RNA will be detected and produce a positive test result; if a person is not infected, no viral RNA will be copied or detected, which will produce a negative test result. Amplification of viral genomic material allows for even small amounts of virus to be detected. This category of diagnostic test includes polymerase chain reaction (PCR) tests, loop-mediated isothermal amplification (LAMP), and clustered, regularly interspaced short palindromic repeat (CRISPR)-based assays.

• There are a wide variety of molecular diagnostics, and some provide faster results than traditional PCR-based methods. These rapid molecular tests include LAMP, which can provide results in minutes rather than hours. Rapid molecular tests that use techniques like LAMP are very specific but also very sensitive because they amplify the genomic material in the patient sample. Importantly, not all rapid diagnostic tests are antigen tests—some are rapid molecular tests that are highly sensitive but provide results in minutes.