Patients with elevated transaminases should not donate blood, as elevated transaminases often indicate liver damage. There are many causes of liver damage, and the common causes are drug-related liver damage, alcohol-related liver damage, and viral liver damage. Drug-related liver injury and alcohol-related liver injury are not contagious, but the hepatitis B and C viruses are contagious and are mainly transmitted through the bloodstream. In the case of hepatitis B or C, the virus can be transmitted to other people through blood donation. To avoid transmission of hepatitis B and C viruses, patients with elevated aminotransferases should not donate blood. Once elevated transaminases are detected, a thorough examination should be performed in a hospital to identify the cause and take treatment.