Test Overview
Cholesterol and triglyceride tests are blood tests that
measure the total amount of fatty substances (cholesterol and
triglycerides) in the blood.
Cholesterol
travels through the blood attached to a
protein. This cholesterol-protein package is called a
lipoprotein. Lipoprotein analysis (lipoprotein profile or lipid profile)
measures blood levels of
total cholesterol,
LDL cholesterol,
HDL cholesterol, and triglycerides.
- Cholesterol. The body uses cholesterol to
help build cells and produce
hormones. Too much cholesterol in the blood can build
up inside arteries, forming what is known as
plaque. Large amounts of plaque increase your chances
of having a heart attack or stroke.
- HDL (high-density lipoprotein) helps remove fat from the body by binding with it in the bloodstream and
carrying it back to the liver for disposal. It is sometimes called "good"
cholesterol. A high level of HDL cholesterol may lower your chances of
developing heart disease or stroke.
- LDL (low-density lipoprotein) carries mostly fat and only a small amount of protein from the liver to other
parts of the body. A certain level of LDL in your blood is normal and healthy because
LDL moves cholesterol to the parts of your body that
need it. But it is sometimes called "bad cholesterol" because a high level may increase your chances of developing heart disease.
- VLDL: (very low-density lipoprotein)
contains very little protein. The main purpose of VLDL is to
distribute the triglyceride produced by your liver. A high VLDL cholesterol
level can cause the buildup of cholesterol in your arteries and increases your
risk of heart disease and stroke.
- Triglycerides are a type of fat the body
uses to store energy and give energy to muscles. Only small amounts are found in the blood. Having a high
triglyceride level along with a high LDL cholesterol may increase your chances
of having heart disease more than having only a high LDL cholesterol
level.
Why It Is Done
Cholesterol and triglyceride testing is
done:
- As part of a routine physical exam to screen for a
lipid disorder.
- To check your response to medicines used to treat lipid
disorders.
- To help determine your chances of having of heart disease,
especially if you have other risk factors for heart disease or symptoms that
suggest heart disease is present.
- If you have unusual symptoms, such as yellow fatty deposits in
the skin (xanthomas), which may be caused by a rare genetic disease that causes
very high cholesterol levels.
Cholesterol and triglyceride screening
Some health organizations recommend that everyone older than
age 20 be checked for
high cholesterol.1 Other organizations recommend cholesterol tests based on age and risk factors for heart disease.2
Talk to your doctor about when you should get a cholesterol test.
For more information, see When to Have a Cholesterol Test.
How To Prepare
Preparation depends on the test. Ask
your doctor which test you are having. You may or may not have to fast. For example, you can get a total
cholesterol test or direct LDL test at any time, even if you recently had a
meal or a snack. But if you get a test that
measures LDL and HDL, you will fast for about 9 to 12 hours.
- If your doctor tells you to fast before your test, do not eat or
drink anything except water for 9 to 12 hours before having your blood drawn.
Usually, you are allowed to take your medicines with water the morning of the
test. Fasting is not always necessary, but it may be recommended.
- Do not eat high-fat foods the night before the test.
- Do not drink alcohol or exercise strenuously before the
test.
Many medicines may affect the results of this
test. Be sure to tell your doctor about all the nonprescription
and prescription medicines and herbs or natural substances you take.
Tell your doctor if you have had a test such as a thyroid or
bone scan that uses a radioactive substance within the last 7 days.
Talk to your doctor about any concerns you have regarding
the need for the test, its risks, how it will be done, or what the results will
mean. To help you understand the importance of this test, fill out the
medical test information form (What is a PDF document?).
How It Is Done
The health professional taking a sample
of your blood will:
- Wrap an elastic band around your upper arm to stop the flow of
blood. This makes the veins below the band larger so it is easier to put a
needle into the vein.
- Clean the needle site with alcohol.
- Put the needle into the vein. More than one needle stick may be
needed.
- Attach a tube to the needle to fill it with blood.
- Remove the band from your arm when enough blood is
collected.
- Put a gauze pad or cotton ball over the needle site as the needle
is removed.
- Put pressure on the site and then put on a bandage.
How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
pinch.
Risks
There is very little chance of a problem from
having blood sample taken from a vein.
- You may get a small bruise at the site. You can lower the chance
of bruising by keeping pressure on the site for several minutes.
- In rare cases, the vein may become swollen after the blood sample
is taken. This problem is called phlebitis. A warm compress can be used several
times a day to treat this.
- Ongoing bleeding can be a problem for people with bleeding
disorders. Aspirin,
warfarin (Coumadin), and other
blood-thinning medicines can make bleeding more likely. If you have bleeding or
clotting problems, or if you take blood-thinning medicine, tell your health
professional before your blood sample is taken.
Results
Cholesterol and triglyceride tests are
blood tests that measure the total amount of fatty substances (cholesterol and
triglycerides) in the blood.
Results are
usually available within 24 hours.
The values listed here are for adult cholesterol levels. Desirable cholesterol and triglyceride levels are slightly different for children and teens. For more information, see Cholesterol in Children and Teens.
Cholesterol and triglycerides 1 Total cholesterol | Desirable: | |
| Borderline high: | - 200–239 mg/dL
- 5.2–6.2 mmol/L
|
| High: | - 240 mg/dL or higher
- 6.2 mmol/L or higher
|
HDL cholesterol | High (desirable): | - 60 mg/dL or higher
- 1.6 mmol/L or higher
|
| Acceptable: | - 40–60 mg/dL
- 1.0–1.6 mmol/L
|
| Low (undesirable): | - Less than 40 mg/dL
- Less than 1.0 mmol/L
|
LDL cholesterol | Optimal: | - Less than 100 mg/dL (less than 70 mg/dL for people at high risk for a heart attack)
- Less than 2.6 mmol/L (less than 1.8 mmol/L for people at high risk for a heart attack)
|
| Near optimal: | - 100–129 mg/dL
- 2.6–3.3 mmol/L
|
| Borderline high: | - 130–159 mg/dL
- 3.4–4.1 mmol/L
|
| High: | - 160–189 mg/dL
- 4.1-4.9 mmol/L or higher
|
| Very high: | - 190 mg/dL or higher
- 4.9 mmol/L or higher
|
VLDL cholesterol | Optimal: | - 30 mg/dL or less
- 0.78 mmol/L or less
|
Triglycerides | Normal: | - Less than 150 mg/dL
- Less than 1.7 mmol/L
|
| Borderline high: | - 150–199 mg/dL
- 1.7–2.3 mmol/L
|
| High: | - 200-499 mg/dL
- 2.3-5.6 mmol/L
|
| Very high: | - 500 mg/dL or higher
- 5.6 mmol/L or higher
|
- An HDL level of 60 mg/dL (1.5 mmol/L) or higher is linked with a lower risk of
heart disease.
- An HDL cholesterol level less than 40 mg/dL (1.0 mmol/L) raises
your risk for developing heart disease, especially if you also have high total
cholesterol levels.
- The ratio of total cholesterol to "good" (HDL) cholesterol may be
important, especially if total cholesterol is high.
- Very high cholesterol and triglyceride levels may be caused by an
inherited form of high cholesterol (hypercholesterolemia or
hyperlipidemia).
- Talk with your doctor about other things that raise
your risk of heart problems. Your doctor may change your goals for cholesterol
levels if you have other risk factors for coronary artery disease, such as:
- Smoking.
- High blood pressure.
- Diabetes.
- Family history of early CAD.
- You are a man and older than 45, or you are a woman and older
than 55.
- If you have a very high risk of having a heart
attack, your doctor may want your LDL level to be less than 70 mg/dL.
- Interactive Tool: Are You at Risk for a Heart Attack?
What Affects the Test
Many conditions can affect cholesterol and triglyceride
levels. Your doctor will talk with you about any abnormal results
that may be related to your other health problems.
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Medicines, such as
diuretics,
corticosteroids, male sex hormones (androgens),
tranquilizers,
estrogen, birth control pills,
antibiotics, and niacin (vitamin B3).
- Physical stress, such as infection,
heart attack, surgery.
- Eating 9 to 12 hours before the test.
- Other conditions, such as
hypothyroidism, diabetes, or kidney or liver
disease.
- Alcohol or drug abuse or withdrawal.
- Liver disease (such as
cirrhosis or
hepatitis), malnutrition, or
hyperthyroidism.
- Pregnancy. Values are the highest during the third
trimester and usually return to the prepregnancy
levels after delivery of the baby.
What To Think About
- Chylomicrons are another type of lipoprotein that are measured in a different test. Chylomicrons are in the blood
and carry fat from your intestine to your liver. They carry triglycerides to your muscles for immediate use. Or they carry triglycerides to fat tissue for storage.
- Having a high cholesterol level increases your chances of having
a heart attack. The higher your cholesterol, the greater your chances. An
elevated total cholesterol level in younger people is particularly significant,
since the narrowing of the
coronary arteries usually takes many years to
develop.
- Lifestyle changes may help lower blood cholesterol levels and increase HDL ("good")
cholesterol. Some people have better responses to diet and lifestyle changes
than do others. Lifestyle changes might include:
- Quitting smoking.
- Eating healthier by reducing saturated (animal) fats and cholesterol in the diet
while increasing fiber and complex
carbohydrate.
- Losing weight. An improvement may occur if you lose as little
as 5 lb (2.5 kg) to
10 lb (4.5 kg).
- Being active on most, preferably all, days of the week.
- Cholesterol screening is often available in supermarkets,
pharmacies, shopping malls, and other public places. Home cholesterol testing
kits also are available. The results of tests done outside a doctor's office or
lab may not be accurate. If you have cholesterol screening done outside your
doctor's office, talk with your doctor about the accuracy of the
results.
References
Citations
- Grundy S, et al. (2002). Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) (NIH Publication No. 02–5215). Bethesda, MD: National
Institutes of Health. Also available online:
http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3full.pdf.
- U.S. Preventive Services Task Force (2008). Screening for lipid disorders in adults. Available online: http://www.uspreventiveservicestaskforce.org/uspstf/uspschol.htm.
Other Works Consulted
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Saunders.
- Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
- Grundy SM, et al. (2004). Implications of recent
clinical trials of the National Cholesterol Education Program Adult Treatment
Panel III Guidelines. Circulation, 110(2): 227–239.
[Erratum in Circulation, 110(6): 763.]
- Miller M, et al. (2011). Triglycerides and cardiovascular disease: A scientific statement from the American Heart Association. Circulation, 123(20): 2292–2333.
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology |
|---|
| Specialist Medical Reviewer | Carl Orringer, MD - Cardiology, Clinical Lipidology |
|---|
| Last Revised | February 1, 2012 |
|---|
Grundy S, et al. (2002). Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) (NIH Publication No. 02–5215). Bethesda, MD: National
Institutes of Health. Also available online:
http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3full.pdf.
U.S. Preventive Services Task Force (2008). Screening for lipid disorders in adults. Available online: http://www.uspreventiveservicestaskforce.org/uspstf/uspschol.htm.
