There are currently 2 types of tests available on the market:
Antigen tests tell you if certain viral proteins are present. These tests are rapid but can be highly inaccurate.
These tell you if a viral genome is present. These tests are highly accurate but are time consuming, expensive, and logistically challenging. Typically, a person’s nose is swabbed, and the sample is shipped to a central lab for processing. Conventional PCR tests require high throughput batches of 500-1000 samples at the same time to be cost effective. Results usually take anywhere from 24-72 hours.
This means that today, when passengers land at an airport and take a PCR test, before they receive their results, they may come into contact with hundreds of people from taxis or public transit to grocery stores, friends and family. With this delay, society is put at risk and governments are required to perform significant contact tracing. It’s not ideal.