Many neuromuscular disorders cause elevated enzymes in the blood, as certain enzymes leak out of damaged muscles, according to the Muscular Dystrophy Association. A genetic mutation inside the cells or an attack from the immune system gradually damages the muscle tissue.
Cells are composed of thousands of enzymes, which serve as catalysts for chemical reactions that take place in the cells, says the MDA. Enzymes are often elevated above normal when a disease or injury damages the cells, causing large amounts of enzymes to leak out in muscles or other parts of the body. Alanine transaminase (ALT) and aspartate transaminase (AST) are the two enzymes typically measured on routine blood tests. Both of these enzymes are found in the heart, muscles, liver and kidneys. AST is also found in the brain, lungs, pancreas and spleen. Conditions that cause damage to the muscle tissue and cause elevated enzyme levels include inflammatory myopathies and muscular dystrophies. Enzymes also leak out of the liver and other organs.
The MDA states that enzyme levels are measured through blood tests, as many enzymes are normally found in the blood. When blood tests reveal higher enzyme levels, physicians investigate the parts of the body that possibly leak enzymes into the blood. After finding the source, they determine why the leak occurred and how to fix it.