Yes, swine flu can show up on a PCR (polymerase chain reaction) test. PCR is a laboratory technique used to detect and diagnose infections caused by viruses, such as the H1N1 virus that causes swine flu. PCR is a highly sensitive test that can detect very small amounts of genetic material from the virus, such as RNA.
When a person is suspected of having swine flu, a sample of their mucus or saliva is taken and tested for the presence of the H1N1 virus using the PCR test. If the virus is present, the PCR test will detect its genetic material and confirm the diagnosis. This test can also be used to monitor the levels of the virus in a person's system over time.
PCR tests are typically very accurate and reliable, but they can sometimes produce false positive or false negative results. In other words, the test may indicate the presence of the virus when it is not actually present, or it may fail to detect the virus when it is present. The accuracy of the test can also be affected by the quality of the sample taken, as well as the technique used to perform the test.