A blood test takes a small sample of your blood which is then sent for testing in a laboratory.

Your doctor or nurse may do it, or you can have your blood test at a hospital, local health clinic or pathology service.

How is the test done?

Blood tests follow this procedure:

Your arm is first cleaned with an antiseptic
A tourniquet (an elastic rope) or a blood pressure cuff is placed around the top part of your arm. This causes the veins in your lower arm to fill with blood.
A needle is inserted into the vein, and the blood is collected in a vial or syringe.

Once your blood is taken, the needle is removed, gentle pressure is put on the area to stop any bleeding, and then a small covering is applied. The whole procedure usually only takes a few minutes.

What does the test show?

When your heart muscle has been damaged, which can happen during a heart attack, your body releases substances into your blood. Blood tests can measure the levels of these substances and show if, and how much of, your heart has been damaged. 

The most common blood test after a heart attack will check levels of a protein called troponin in your blood. Blood tests are also done to measure the level of other substances in your blood, such as blood fats (e.g. cholesterol and triglycerides) and minerals.

The blood test can also show how your body’s organs are functioning, such as your kidneys, liver or hormone-producing glands. This information helps to guide treatment and diagnosis.

Why is the test done?

A blood test can confirm if you’ve had a heart attack and measures the extent of the damage. It will also help your doctor work out your future risk of heart disease.

Preparing for the test

There is no special preparation. Your doctor or healthcare provider might ask you to fast before the test, but you should check if this is necessary for your individual health situation. You should make sure you’re not dehydrated by keeping up your fluid intake, as this can make your veins easier to find for the test.

For more information about blood tests, speak to your doctor, nurse or health worker.