Blood. Hepatitis a can be checked by looking for antibodies that show up in your body after exposure. Liver function is more complicated and we usually check liver enzymes that suggest inflammation and damage and protein, bilirubin and clotting levels which can show how well the liver is doing its job in making the proteins and cleaning the blood.
Easy blood testing. Hepatitis a is preventable--it is spread by fecal-oral route, & good vaccine exists. It can occur sporadically or in epidemic form. Disease in children is often mild & frequently subclinical or little more than gastroenteritis, but more serious & prolonged in adults. Rare fulminant form with marked jaundice, or "relapsing" course that eventually resolves. Is never chronic nor leads to cirrhosis.