BMJ Group Medical Reference
Troponin is a protein found in your heart muscle and in your other muscles.  If your heart muscle is damaged, troponin gets into your blood. So how much troponin you have in your blood helps doctors to work out whether you have unstable angina or have had a heart attack.
Unstable angina can sometimes turn into a heart attack. That means you will need to have more than one troponin test. You will probably have one when you first get to hospital and another one some hours later. 
From the results of your troponin test, doctors will be able to work out whether you need to be treated for a heart attack. If the test is negative, doctors need to find out how high your risk is of having a heart attack or other serious heart problems later on. This will affect what treatment you have. For more, see Unstable angina: working out your risk.
Doctors call a heart attack an acute myocardial infarction (or acute MI). This is the name for the damage that occurs to the heart muscle if it isn't getting enough blood and oxygen because a branch of the coronary arteries is blocked. During a heart attack, you may have pain or heaviness over your chest, and pain, numbness or tingling in your jaw and left arm.
A lot of your body's tissues are made out of proteins. Proteins can be made in your cells. Proteins are also part of the food you eat, particularly meat and dairy products. Your body breaks down the protein you eat into amino acids. Your cells then use these amino acids to build new proteins, which make up muscles, joints, hair and other parts of your body.
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