Elevated ALT and AST levels may indicate hepatitis A, B or C, heart failure or nonalcoholic fatty liver disease, according to Mayo Clinic. Additional causes include drinking alcohol or taking medications such as statins or acetaminophen. Obesity, alcoholic hepatitis, liver cancer and hypothyroidism also cause elevated liver enzyme levels.
Other possible causes of high ALT and AST levels include Wilson's disease, cirrhosis, inflammation of the gallbladder and pancreatitis, explains Mayo Clinic. Most often, elevated liver enzymes are only slightly elevated and do not indicate a problem with the liver. This condition is normally only temporary. ALT stands for alanine transaminase, and AST stands for aspartate transminase; however, when ALT and AST levels are both present in the blood in higher than normal amounts, liver damage is highly likely, states BootsWebMD.
The liver is responsible for both filtering and processing the blood in the body, according to BootsWebMD. It also metabolizes the nutrients in a person's body, helps with blood clotting and detoxifies substances that can cause harm. Proteins in liver cells are referred to as enzymes. These enzymes, such as ALT and AST, make the aforementioned processes possible. A damaged liver allows these enzymes to leak into the blood, which allows blood tests to detect them.