HIV To diagnose an individual with HIV, a test must be taken to determine if the virus is present in their system. There are several test options including ELISA, at-home, saliva, viral load, and western blot. To establish the presence of the HIV virus, some tests measure the level of HIV antibodies in the blood and/or saliva or the level of both HIV antigens and antibodies in the blood. Other tests can detect the presence of the HIV virus by calculating the amount of actual virus present in the blood. None of the tests available can determine if a person is positive immediately after they believe they have been exposed to the virus. Each test has a window of time after the initial exposure occurred until the test can accurately tell if an individual has been infected or not. One reason for this is because the focus of some of the tests are antibodies. After the initial exposure to the virus, it usually takes 3–4 weeks but it can take up to six months for antibodies to be produced by the body. For nucleic acid tests, like the viral load blood test, it can take anywhere from 10–33 days for the test to provide an accurate result. If an individual's first HIV test is positive, it is recommended for them to take a second test to confirm the results. If this follow-up test is also positive, an HIV positive diagnosis can likely be made. HCV For an individual to be diagnosed with HCV, they must first take the<unk>  C antibody (HCV Ab) screening test. This test is used to determine the presence of HCV antibodies in the blood. It can take anywhere from 3–12 weeks after the time of initial exposure for antibodies to appear in the blood. Therefore, even if a person is infected with HCV, an HCV Ab test may not show a positive result until after that amount of time has passed. If the HCV Ab test result is positive for HCV antibodies, then the individual either has an active HCV infection or previously had an infection which has since cleared. The individual must follow-up with a quantitative and/or qualitative HCV RNA blood test which provides a count of the HCV viral load and indicates if the infection is chronic or not. The virus RNA can be detected in the blood 1–2 weeks after exposure. For a quantitative test, a low viral load is any value below <800,000 IU/L and anything above 800,000 IU/L is considered a high viral load. Lower viral loads at the start of treatment have been associated with greater likelihood to clear the infection. A positive result for a qualitative HCV RNA blood test confirms that the active virus is present in the individual's bloodstream and that the infection is chronic. A negative result can indicate that the person's immune system was able to spontaneously clear their body of the infection without treatment. Lastly, there is an HCV genotype test which is done to identify the particular genotype (or strain) of the HCV virus the individual is infected with. There are a total of six different HCV genotypes. Knowing the specific genotype of the virus is important when deciding on treatment options because some antiviral medications are more effective against certain genotypes.
Hepatitis C and HIV coinfection
HIV superinfection
Tuberculosis in relation to HIV
Epstein–Barr virus infection
HPV-positive oropharyngeal cancer
Latent autoimmune diabetes in adults
Smoking in South Korea
History of coronavirus