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Blood Tests to Determine Risk of Coronary Artery Disease

These blood tests help to determine your risk for coronary artery disease and heart attack and guide your treatment.

Lipoprotein a (Lp(a))

“Non-traditional” blood protein associated with higher risk of heart attack and stroke.

Goal values:
  • Desirable level for adults: less than 30 mg/dL

Blood should be collected after a 12-hour fast (no food or drink, except water). For the most accurate results, wait at least two months after a heart attack, surgery, infection, injury or pregnancy to check this blood level.

Lp(a) is LDL (low density lipoprotein) attached to a protein called apo (a). It is not fully known what Lp(a) does, but if Lp(a) is greater than 30 mg/dL, it is related to an increased risk for heart attack and stroke. It is also related to development of fatty matter in vein grafts after bypass surgery, coronary artery narrowing after angioplasty and increased risk for the development of blood clots. If Lp(a) is high, it is even more important to bring the LDL levels down to an acceptable level. Lp(a) is higher in African Americans. The causes of high Lp(a) are kidney disease and certain family (genetic) lipid disorders.

Apolipoprotein A1 (Apo A1)

Apo A1 is the major protein of HDL. Low levels of Apo A1 is associated with increased risk of early cardiovascular disease, and may be seen more often in patients with a high-fat diet, inactivity and central obesity.

Goal values:
  • Desirable level for adults: more than 123 mg/dL

Blood should be collected after a 12-hour fast (no food or drink, except water). For the most accurate results, wait at least two months after a heart attack, surgery, infection, injury or pregnancy to check this blood level.

Apolipoprotein B (ApoB)

A major protein found in cholesterol particles. New research suggests ApoB may be a better overall marker of risk than LDL alone.

Goal values:
  • Less than 100 mg/dL for those with low/intermediate risk
  • Less than 80 mg/dL for high-risk individuals, such as those with cardiovascular disease or diabetes

Blood should be collected after a 12-hour fast (no food or drink, except water). For the most accurate results, wait at least two months after a heart attack, surgery, infection, injury or pregnancy to check this blood level.


A protein found in the blood. Encourages blood clotting, but high levels are linked to an increased risk for heart attack and vascular disease.

Goal values:
  • Less than 300 mg/dL

Blood should be collected after a 12-hour fast (no food or drink, except water). For the most accurate results, wait at least two months after a heart attack, surgery, infection, injury or pregnancy to check this blood level.

Higher blood pressure, body weight, LDL and age are related to higher levels of fibrinogen. On the other hand, alcohol use and exercise are related to lower fibrinogen levels. Higher fibrinogen levels are also seen with African Americans, and a rise is seen with menopause.

N-terminal-pro-B-type Natriuretic Peptide (NT-proBNP)

"Non-traditional" blood protein made in the heart and found in the blood. High levels are associated with increased risks of cardiovascular disease, heart attack and heart failure development. Elevated levels are associated with development of heart failure and worse prognosis.

Goal values:
  • Less than 125 pg/mL

This test may be performed any time in the day without fasting.

LDL-associated PLA2 (PLAC)

This blood test measures the level of lipoprotein associated-phospholipase A2 (Lp-PLA2), an enzyme associated with inflammation, stroke and heart attack risk. However, elevated levels also may be due to non-arterial causes.

Goal values:
  • Less than 200 ng/mL (normal value) for low relative risk of CVD
  • Between 200-235 ng/mL for intermediate relative risk of CVD
  • More than 235 ng/mL for high relative risk of CVD

A 12-hour fast (no food or drink, except water) is required for this blood test. Wait at least two months after a heart attack, surgery, infection, injury or pregnancy for best results.

Urine Albumin/Creatinine Ratio (Ualb/Cr)

Albumin is a protein found in urine that can be a sign of increased risk for kidney disease, diabetes complications and cardiovascular risks. If elevated levels of Ualb/CR are present, close attention to blood pressure control, including use of specific blood pressure medications that help protect the kidney, may be recommended. Aggressive global preventive risk reduction efforts, such as closer attention to lipid levels, blood pressure control and diabetes control, are suggested.

Goal values:
  • More than 30 mg/g indicates increased risk for CVD and diabetic nephropathy
  • More than 300 mg/g indicates clinical nephropathy

A clean catch spot urine test can be performed any time in the day and does not require fasting.

Global Risk Score (GRS)

A tool that looks at a person’s risk factors, weighs them in importance and then gives a percentage risk of that patient developing heart disease or of having a heart attack within the next 10 years.

Goal values:
  • Less than 10% = low risk
  • 10 – 20% = intermediate risk
  • Greater than 20% = high risk

What is High Sensitivity C-reactive Protein (HS-CRP)?

Inflammation (swelling) of the arteries is a risk factor for cardiovascular disease. It has been linked to an increased risk of heart disease, heart attack, sudden death, stroke, and peripheral arterial disease. It has also been linked to an increased risk of restenosis, or the re-closing of an artery that has been treated with balloon angioplasty.

High Sensitivity (also called Ultra-sensitive) C-reactive protein is known as HS-CRP, US-CRP or CRP for short. It is a protein found in the blood and what we call a "marker" for inflammation, meaning its presence indicates a heightened state of inflammation in the body. Inflammation is a normal response to many physical states including fever, injury and infection. Inflammation plays a role in the initiation and progression of cardiovascular disease.

CRP and Cardiovascular Risk

In studies involving large numbers of patients, CRP levels seem to be correlated with levels of cardiac risk. In fact, CRP seems to be at least as predictive of cardiac risk as cholesterol levels. The Physicians Health Study, a clinical trial involving 18,000 apparently healthy physicians, was the first large study to show that elevated levels of CRP were associated with a threefold increase in the risk of heart attack.

In the Harvard Women's Health Study, results of the CRP test were more accurate than cholesterol levels in predicting coronary problems. Twelve different markers of inflammation were studied in healthy, postmenopausal women. After three years, CRP was the strongest predictor of risk. Women in the group with the highest CRP levels were more than four times as likely to have died from coronary disease, or suffered a nonfatal heart attack or stroke. This group was also more likely to have required a cardiac procedure such as angioplasty or bypass surgery than women in the group with the lowest levels.

More recently, the JUPITER (Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin) study has shown that statins prevent heart disease and lower risks of stroke, heart attack - and death -  in individuals with normal levels of LDL (the  bad cholesterol), but elevated levels of “high-sensitivity C-reactive protein” or CRP.

How can I be tested?

A simple blood test can be done at the same time as a cholesterol screening. The high-sensitivity C-reactive protein (HS-CRP) test, helps determine heart disease risk and is widely available. Patients should ask their doctors about HS-CRP specifically.

The American Heart Association recommends HS-CRP as part of routine screening for those who are at intermediate risk for heart disease. Cleveland Clinic has used the HS-CRP test routinely for at-risk patients for several years. It is a useful test for people with one or two risk factors who wonder if they are at risk of heart attack or stroke. The JUPITER study results suggest that people even with minimal risk factors in an older age group (late 50s to early 60s) should have their CRP tested and treated accordingly.

Ultra Sensitive C-Reactive Protein Blood (HS-CRP)

  • C-reactive protein measures an inflammatory response in the body and has been shown to play a role in atherosclerosis and blood clot formation. 
  • Patients should ask their doctor specifically about HS-CRP, as this test helps determine heart disease risk. Elevated HS-CRP is related to increased risk for heart attack, restenosis of coronary arteries after angioplasty, stroke, and peripheral vascular disease (PVD).
  • While elevated cholesterol, LDL and triglycerides and low HDL are all independent risk factors for heart disease and cholesterol build-up, HS-CRP provides additional information about inflammation in the arteries – something not determined by lipid testing alone.
  • Less than 1.0 mg/L = Low Risk for CVD
  • 1.0 – 2.9 mg/L = Intermediate Risk for CVD
  • Greater than 3.0 mg/L High Risk for CVD

Readings of 50 and above are possible, but we generally attribute a level higher than 10 to inflammation due to other conditions, such as an infection, illness, or a serious flare-up of arthritis, can raise CRP levels.

Therefore, testing should not occur while ill or injured. The HS-CRP should be ordered to evaluate CVD risk in apparently healthy individuals who have not had recent infection or other serious illness. Those who have levels of higher than 10 should be evaluated for other sources of inflammation.


This test may be measured any time of the day without fasting.

What can I do if my HS-CRP level is high?

A high HS-CRP should be treated by aggressive risk factor reducing strategies. These include lifestyle change, such as:   

  • Eating a heart-healthy diet
  • Reducing high cholesterol levels
  • Maintaining a healthy weight
  • Exercising regularly
  • Managing diabetes and high blood pressure
  • Quitting smoking or tobacco use
  • Drinking less alcohol

Cholesterol-lowering statin drugs both reduce CRP and LDL and lower cardiac risks. Antithrombotic medications such as low dose aspirin or clopidogrel may provide protection as well. Your doctor will prescribe the correct medications and dosage to treat your condition.

HS-CRP: Improve Your Cardiovascular Health

HS-CRP, combined with a global risk evaluation can provide an overall view of cardiovascular risk. This information is important to develop a plan to improve your cardiovascular health. Call the Preventive Cardiology and Rehabilitation Program at 216.444.9353 or toll-free 800.223.2273, ext. 49353 to be evaluated and get started.

For More Information

Reviewed by Dr. Leslie Cho, Director of the Cleveland Clinic’s Women’s Cardiovascular Center and Section Head, Preventive Cardiology and Rehabilitation at the Sydell and Arnold Miller Family Heart & Vascular Institute at Cleveland Clinic.

What is MPO?

MPO is short for myeloperoxidase. MPO is an enzyme. Enzymes are special types of protein found in the body that cause chemical changes. MPO is usually stored in a certain type of white blood cell. These cells release MPO when blood vessels are injured or become inflamed.

How is MPO related to heart attack?

Your MPO level is a way to assess your risk of heart attack. Research shows that when arteries get inflamed on the inside, it can lead to a heart attack. As cholesterol and fat (plaque) collect and build up in the artery walls, the artery wall becomes inflamed. Eventually, the inflammation gets bad enough that the plaque bursts through the artery wall and into the blood, causing a clot to form. When a clot completely blocks blood flow to the heart, it causes a heart attack.

MPO plays a role in the inflammation in the artery wall. It also gets released when inflammation occurs. MPO in the blood can also accumulate in the artery wall, so MPO that is released from other areas of the body that are inflamed (like an inflamed joint or even gum disease) can collect inside the arteries. Multiple studies show that the plaque in the artery walls contains large amounts of MPO. This is especially true in places that are prone to rupture and can lead to heart attacks. White blood cells in the blood also seem to release more MPO into the bloodstream when the artery wall becomes inflamed, causing a “vicious cycle.” Studies show that the inflammation and release of MPO can happen years before a heart attack occurs.

Once MPO is released, it increases the risk of heart attack in several ways:

  • MPO changes low-density lipoprotein (LDL/”bad”) cholesterol into an even more harmful form that easily collects as plaque in the arteries.
  • MPO produces a substance that directly damages the artery wall. This makes the plaque unstable and more likely to rupture.
  • MPO interferes with the protective effects of high-density lipoprotein (HDL/”good”) cholesterol. It also keeps the body from getting enough nitric oxide, a substance in the body that expands blood vessels.

Why should I have my MPO level tested?

Measuring the level of MPO in your body can help your doctor identify inflammation in your arteries. If you have inflammation, it means you are at a higher risk of having a heart attack.

The test lets people with an otherwise low risk of heart attack find out if they have a higher risk than they know. Patients with known coronary artery disease, chest pain or other risk factors can also benefit from getting their MPO level checked. Studies show that, among patients with chest pain, an increased MPO level can predict their risk of heart attack over the next 30 days to six months. In other, longer studies involving middle-aged patients who were assumed to be healthy, an elevated MPO level predicted the risk of heart attack over two to 10 years.

When is the MPO test performed?

If your doctor recommends that you have an MPO test, it will likely be done at the same time as other blood tests, such as a cholesterol test.

How should I prepare for the MPO test?

Your MPO level will be checked with a simple blood test. You do not need to follow any special instructions for the test. It can be done at any time of the day. You do not need to fast or stop taking any medications. But, if you are having blood drawn for other tests, you may need to follow special instructions not related to the MPO test.

What do the test results mean?

Goal: <400 pmol/L

Low risk: 400 - 480 pmol/L

High risk: ≥480 pmol/L

What should I do if my MPO level is high?

If your MPO level is high, your doctor may want you to have some more tests. You should talk to your doctor about what you can do to lower your MPO level and reduce your overall cardiovascular risk. To help reduce your risk, your doctor may recommend that you:

  • Eat a heart-healthy diet. This means eating foods that are low in fat and including lots of fruits, vegetables and whole grains in your diet.
  • Reach and stay at a healthy weight.
  • Keep your blood pressure under control. If you have high blood pressure, follow your doctor’s recommendations for medications, exercise and diet.
  • Quit smoking, if you smoke.
  • Increase your level of physical activity.
  • Work with your doctor to be more aggressive to prevent cardiovascular problems. This can include lowering your LDL cholesterol level, paying closer attention to your blood pressure, managing your weight, and exercise.

Is the MPO test covered by insurance?

Most commercial insurance companies and Medicare cover the cost of the MPO test. If you have a question about your coverage, please contact your insurance provider.

Where can I get more information about MPO and MPO testing?

To learn more about MPO and MPO testing, contact a Sydell and Arnold Miller Family Heart & Vascular Institute Resource & Information Nurse. You can chat online with a nurse or call 216.445.9288, or toll-free at 800.289.6911.

Reviewed: 01/13

This information is about testing and procedures and may include instructions specific to Cleveland Clinic. Please consult your physician for information pertaining to your testing.

Talk to a Nurse: Mon. - Fri., 8:30 a.m. - 4 p.m. (ET)

Call a Heart & Vascular Nurse locally 216.445.9288 or toll-free 866.289.6911.

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