Cardiac Laboratory Testing

If you have risks for heart disease or stroke, your doctor may order several laboratory tests to evaluate your condition. Among these tests are the CRP, fibrinogen, homocysteine, cholesterol, lipoprotein (a), and BNP.

C-Reactive Protein (CPR)

CRP levels are correlated with risk for heart disease. The Physicians Health Study found that elevated levels of CRP give you a threefold increased risk of a heart attack. Also, CRP was found to be the strongest predictor of heart disease risk in women. Certain conditions and infections can raise CRP levels, including arthritis and influenza.

CPR is measured by a simple laboratory blood test. Heart disease risk is determined by the results of your high-sensitivity CRP. If the level is less than 1.0 mg/L, your risk is low. If your level is between 1.0 and 2.9, your risk is intermediate or moderate. For those with a level greater than 3.0, the risk is considered high.

Fibrinogen

Fibrinogen is a protein found in the blood that helps with clotting. Too much of this substance can cause clots to form in your arteries, leading to a stroke or heart attack. When fibrinogen levels are high, this could indicate atherosclerosis and also worsen existing artery wall injury.

If you are at risk for heart disease, the Phoenix cardiologist will check your fibrinogen level. Smoking, alcohol consumption, inactivity, and estrogen therapy all can increase this protein level. A normal fibrinogen level is between 200 and 400 mg/L.

Homocysteine

A substance used by the body to make protein, build tissue, and maintain muscle is homocysteine. Too much of this substance can increase your risk for heart disease, peripheral artery disease, or stroke. Homocysteine levels can drop if you take folic acid supplementation or eat more foods that contain B vitamins.

If you have had cardiovascular problems, and do not have the traditional risk factors, your cardiologists in Phoenix may check a homocysteine level. Also, it is done if you have a family member who developed heart disease at a young age or had high homocysteine levels. A normal level of this substance is between 4.4 and 10.8 umol/L.

Cholesterol Tests

A comprehensive cholesterol panel is called a lipid profile. These tests measure the fats (lipids) in your circulating blood. The components of a lipid profile are:

• Total Cholesterol (TC) – This is the sum of blood cholesterol. A high level indicates risk for heart disease. A normal total cholesterol is below 200 mg/dL.
• Low-Density Lipoprotein (LDL) – The LDL is the “bad” cholesterol. This accumulates in your arteries leading to atherosclerosis, which reduces the flow of blood and causes clot formation. A normal LDL is less than 130 mg/dL.
• High-Density Lipoprotein (HDL) – The HDL is the “good” cholesterol. It helps carry the LDL cholesterol out of the bloodstream. A good level of HDL is higher than 60 mg/dL.
• Triglycerides (TG) – Another type of fat in the blood is TG. High levels of TG mean that you eat more calories than you should. This puts you at risk for heart disease. A normal level of TG is less than 150 mg/dL.

Lipoprotein (a)

Lipoprotein (a) is often called Lp(a). This is a type of LDL cholesterol that is determined by your genetic makeup. High levels of this substance indicate a risk for heart disease. The Lp(a) test is a simple blood test done if you have a family history of early-onset heart disease or if you do not respond to cholesterol treatment.

Brain Natriuretic Peptides (BNP)

BNP is a type of protein that your blood vessels and heart manufactures. This substance helps eliminate fluid from the body by relaxing the blood vessels and taking sodium into the urine.

When your heart becomes damaged, the body secretes high levels of BNP into the blood to attempt to ease the heart strain. These levels also rise during a heart attack or with angina. This level is also helpful in diagnosing and assessing heart failure.