IMA

This test measures the amount of ischemia-modified albumin present in the blood. Albumin is a protein produced by the liver. It normally makes up about 60% of the protein found in the bloodstream. Albumin is important in helping to regulate the amount of fluid in the blood vessels and in transporting other compounds throughout the body. When myocardial ischemia (a decrease in the supply of oxygen to the heart) occurs, it changes some albumin molecules. Within a few minutes, and persisting for several hours, ischemia decreases albumin’s ability to bind to metals such as cobalt. The discovery of this property led to the development of a test that measures the amount of ischemia-modified albumin by measuring the reduction in metal binding.

Myocardial ischemia may be caused by the partial or complete blockage of a blood vessel or a narrowed or constricted blood vessel. A blockage can decrease or prevent blood flow to the heart. It can cause a heart attack (myocardial infarction, MI) and permanently damage or kill heart muscle cells.

Temporary myocardial ischemia may be seen with angina, an episodic condition associated with the gradual narrowing of one or more blood vessels and with arterial spasms. Angina is triggered when the body cannot respond adequately to increased oxygen demands, and it usually resolves with rest. In some cases, angina can become unstable (occurring at rest or becoming more severe) and escalate to cause a heart attack. Both unstable angina and MI are collectively known as acute coronary syndrome (ACS). Symptoms vary but may include chest pain and pressure that occur at rest or persist despite rest, shoulder pain, neck pain, nausea, and shortness of breath.

Patients with these symptoms are typically evaluated in the emergency room. There, the doctor must try to rapidly differentiate ACS from other conditions with similar presentations and try to distinguish between the various causes of ACS. To do this, he may order cardiac biomarkers, tests such as troponin and myoglobin, to detect damage to the heart, and an electrocardiogram (ECG) to look for heart damage. If these tests are clearly abnormal, then the patient is started on treatment for MI.

If the tests are not definitive, then determining whether the patient is experiencing temporary angina, is at a significant risk of having a heart attack in the near future, or if they can be safely sent home can be a challenge. Researchers are looking for tests that can help guide the doctor’s decision-making in this situation. The ischemia-modified albumin test is a potential candidate for this role.

A blood sample is obtained by inserting a needle into a vein in the arm.