PCR tests, or Polymerase Chain Reaction tests, are laboratory techniques used to detect the presence of specific genetic material from viruses or other organisms. They work by amplifying small amounts of DNA or RNA, making it easier to identify if a particular pathogen, such as the SARS-CoV-2 virus that causes COVID-19, is present in a sample. The process involves collecting a sample, often from a nasal swab, and then using enzymes to replicate the target genetic material. This method is highly sensitive and can provide results within a few hours to a few days, making it a crucial tool in diagnosing infections and monitoring outbreaks.