Cardiovascular function tests

The most common blood tests used in the diagnosis and management of cardiovascular disease include:

• Antistreptolysin-O test. Streptolysin is a protein produced by streptococcal bacteria. In response to infection, the body mounts an immune response that relies on antibodies to identify the streptolysin. High levels of antibodies for streptolysin, called antistreptolysin-O antibodies, may indicate the presence of an infection from strep, such as endocarditis (an inflammation of the lining of the heart or valves) or rheumatic fever.
  
  
• Arterial blood gases. This test takes a sample of blood from an artery in the side of a wrist (which carries oxygen-rich blood) instead of a vein in the crook of the arm (which carries oxygen-poor blood). The sample gives information about levels of oxygen (which should be high) and carbon dioxide (which should be low).
  
  
• Blood fat profile. Also called a lipid panel, this test measures fats and fat-like substances in the blood that, if abnormally high, have been associated with heart disease. In a standard lipid panel, fats measured include:
  
  
• • Total cholesterol. A high total cholesterol level is associated with heart disease.
    
    
  • LDL cholesterol. Low-density lipoprotein or “bad” cholesterol that is associated with atherosclerosis.
    
    
  • HDL cholesterol. High-density lipoprotein or “good” cholesterol” that protects against heart disease.
    
    
  • Triglycerides. High levels are associated with heart disease.
    
    
  • VLDL (very low density lipoprotein). Another carrier of fat in the blood, that is associated with atherosclerosis.
    
    
• Blood calcium test. By measuring the calcium levels of blood, a physician may be able to support the diagnosis of a number of cardiovascular problems. Calcium is important for proper blood clotting, and abnormal levels may signal kidney or thyroid disorders.
  
  
• BNP blood test. This new test measures the level of hormone called B-type natriuretic peptide, which has been shown to rise in heart failure.
  
  
• C-reactive protein test (CRP test). CRP is an inflammatory marker – a substance that the body releases in response to inflammation. CRP levels can provide physicians with information about a patient’s risk of having a heart attack or stroke.
  
  
• Carbon dioxide content. CO2 levels are generally used as an investigative and diagnostic tool for patients with breathing problems. This analysis may be helpful in the diagnosis of conditions such as chronic obstructive pulmonary disease (COPD).
  
  
• Complete blood count (CBC). This very common test can provide important information about the types of blood cells present and their condition and number (percentage) in relation to other cells. An elevated white blood count (WBC) may indicate a heart attack, infection or inflammatory disease, such as rheumatoid arthritis.
  
  Elevated levels of red blood cells, hematocrit (the percentage of available space taken up by red blood cells) or hemoglobin (the protein molecule in red blood cells that carry oxygen) may indicate a lack of oxygen in the body. This may be caused by smoking, congenital heart disease (a cardiac abnormality, defect or malformation that is present from birth), dehydration or kidney disease. Low hemoglobin or hemocrit may suggest anemia. Anemia may suggest bleeding complications in patients receiving anticoagulants.
  
  
• Electrolyte panel. Tests that measure the amount of potassium, sodium, chloride and carbon dioxide levels in the blood in order to assess how well the major organ systems (e.g., the heart and cardiovascular system) are functioning.
  
  
• Erythrocyte sedimentation rate (ESR). A test that measures the rate at which red blood cells separate from plasma (the liquid part of blood) and fall to the bottom of a test tube to form a sediment. High levels may occur during a heart attack, rheumatic fever, giant cell arteritis, severe anemia, cancer relapse or other conditions. Low levels may be associated with heart failure, sickle cell anemia or other conditions.
  
  
• Cardiac enzyme tests. This test measures a number of heart enzymes, including creatine phosphokinase (CK). CK is a valuable tool for determining whether a heart attack is the cause of chest pain. Levels of CK typically rise within four to eight hours of a heart attack and return to normal by 72 hours after the heart attack.
  
  
• Glucose test. This is primarily used to screen for, diagnose or monitor patients with diabetes, a metabolic condition in which blood glucose levels are too high because the body cannot produce enough insulin in the pancreas or is desensitized to the effects of insulin. Following a heart attack or other serious illness, fasting glucose levels may be temporarily high.
  
  
• INR/prothrombin time tests. A type of coagulation test that measures how long it takes blood to clot. Prothrombin is a protein substance that needs to be converted to thrombin in order for clotting to occur. People taking anticoagulants (such as warfarin) may have this test done regularly.
  
  
• Serum myoglobin test. A test sometimes used to measure the damage done to the heart muscle after a heart attack.
  
  
• Total serum protein. Blood contains large amounts of protein, and measuring these levels can give physicians valuable information about a patient’s nutritional state and kidney and liver functions. Abnormal protein levels may indicate congestive heart failure, high blood pressure (hypertension), or kidney or liver disease.
  
  
• Waste products test. A group of blood tests that measure the levels of specific waste products in the blood, including blood urea nitrogen, creatinine and uric acid. Abnormal results could be a sign of heart failure, heart attack or kidney disease.