Blood Tests
In
many ways a physician is like a detective. He or she has to
sort out the information described by you about your symptoms
and medical history, perform a physical exam and diagnostic
tests, and finally diagnose the problem. Diagnostic tests
that are performed in physicians' offices and at the Inova
Heart Center in both out patient clinics and in patient settings
include the following:
Everyone who has had a heart attack is immediately admitted to a specialized critical care unit where nurses are experts in caring for you. Some individuals are admitted to the hospital because a heart attack is not yet confirmed, or because further diagnostic testing are needed. At times, individuals are monitored and released from the emergency room to home, after a heart attack has been ruled out. It is important for them to obtain follow-up with their personal physician.
What do all these blood tests show?
Routine blood tests help to diagnose conditions or determine the absence of a problem.
Blood tests that are specific to cardiology include the following:
- Cardiac Enzymes - When someone experiences chest pain, blood will be checked for elevated cardiac enzymes to determine the presence of heart damage. Enzymes or other cardiac markers are usually found in the heart cells and leak into the bloodstream after a heart attack. The presence of enzymes is one of the indicators that confirms a heart attack. Whether or not a heart attack has been confirmed, cardiac enzymes are drawn at prescribed intervals to be sure that the enzyme levels are decreasing, or to see whether cardiac enzymes that did not show up during the initial blood draw show up during subsequent blood draws.
- International Normalized Ratio (INR) - The INR is a reliable and accurate blood test that monitors oral anticoagulation therapy (a medication that thins the blood), something that is common for individuals with artificial prosthetic heart valves or atrial fibrillation. The Inova Heart Center has developed protocols for INR for patients having heart valve surgery as well as for patients with atrial fibrillation.
- Lipid profiles - Lipid levels are obtained to assess risk for cardiovascular disease. See cholesterol for more information about lipid profiles.
- Oxygen level - The measurement of oxygen in the bloodstream via a blood specimen taken from an artery helps determine whether the heart is pumping effectively, whether the lungs are providing enough oxygen, and whether there is shunting of blood in the heart (this prevents blood from traveling through the lungs to pick up oxygen). Oxygen levels can reflect considerable heart damage, heart failure and shock. Blood oxygen content can also be analyzed on an ongoing basis, using a clip that is attached to a fingertip, and via a catheter that is placed in an artery and left in place.
- Prothrombin time - Many individuals with heart disease take medications to slow the process of blood clotting. These medications are prescribed to individuals who are predisposed to blood clots (individuals with artificial heart valves or with atrial fibrillation) or who have a history of having blood clots (individuals with deep vein thrombosis, pulmonary embolism, and, in some instances, heart failure). The medication prescribed to these individuals thins the blood, but not in any predictable way. Thus, the prothrombin time is monitored (more frequently when the medication is first prescribed, then eventually about once a month). The results of the prothrombin time will lead to adjustments in the dosage of the blood thinning medication.
