What are enzyme markers?

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1 What are enzyme markers? Enzymes are highly specialized complex proteins that aid chemical changes in every part of the body. For example, they help break down food so your body can use it effectively. They also help your blood clot. And they re present in every organ and cell in your body. Enzymes are necessary for your body to function properly. Enzyme markers are blood tests that analyze specific enzyme activity in the body. Some inherited diseases or conditions can cause these enzymes to stop working or be less efficient. Monitoring the rise or fall of enzyme levels can aid in the diagnosis of a variety of conditions. This work is licensed under a Creative Commons Attribution- ShareAlike 4.0 International License.

2 What are the common types of enzyme markers? CPK isoenzymes The CPK isoenzymes test measures the creatine phosphokinase (CPK) in the blood. CPK enzymes are in the heart, brain, and skeletal muscles. Normal CPK levels vary by age, gender, and race. Each laboratory may have minor differences in reference ranges, as well. In general, a CPK level of approximately 200 units per liter (U/L) or less is considered normal in an adult. This is the total CPK level in your body. More specific testing can be done, but this is not routine.

3 CPK ISOFORMS CPK-1 resides mostly in the brain and lungs. Increased levels of CPK-1 can be due to: brain cancer CPK-2 levels rise following a heart attack. Increased levels of CPK-2 may also be due to: open heart surgery inflammation of the heart muscle heart injury defibrillation electrical injuries chest compressions after cardiac arrest High CPK-3 levels can be a sign of muscle stress, a crush injury, or injury due to: muscle damage, dystrophy, or inflammation intramuscular injections electromyography, which is a muscle and nerve function test recent surgery seizures strenuous exercise

4 Heart enzymes Some heart enzymes slowly enter your blood if you ve had a heart attack and your heart is damaged as a result. A general test for emergency room patients with heart attack symptoms is a test for the presence of certain proteins in your blood. A doctor may check CPK-2, also known as CK-MB. This marker is highly specific for heart muscle injury and rises rapidly during a heart attack. Normal CK-MB should be between 5-25 international units per liter (UI/L). The preferred marker of heart injury, though, is a protein called troponin. Troponin should generally be less than 0.02 nanograms per milliliter (ng/ml). The level takes longer to rise than CK-MB, but the protein stays in the bloodstream longer.

5 Liver enzymes Elevated liver enzymes may be due to inflammation or damaged liver cells. Usually, elevated liver enzymes are related to an acute injury, or a process that occurred over a short period of time due to: prescription medications, such as statins over-the-counter (OTC) medications, such as acetaminophen (Tylenol) alcohol consumption heart failure or heart attack liver disease, such as hepatitis, fatty liver disease, cancer, and cirrhosis obesity celiac disease, which is a digestive condition viruses, such as cytomegalovirus infection; hepatitis A, B, C, E viruses; mononucleosis; and Epstein-Barr Virus hemochromatosis, which is a disorder in which there s too much iron in the blood physical trauma to the organ

6 There are several markers that can be used to test liver function. These markers help separate whether or not the injury is to the liver parenchyma (liver cells) or to the biliary system. The important tests are the liver aminotransferases: alanine aminotransferase (ALT) and aspartate aminotransferase (AST). ALT is primarily produced by the liver, while AST can be from the liver, cardiac muscle, skeletal muscle, kidney, and brain. A normal ALT level is IU/L for men, and IU/L for women. A normal AST level may range from IU/L for men and 9-32 IU/L for women. These reference ranges vary from hospital to hospital. It s important to compare your liver enzyme levels to the reference ranges provided by the lab.