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Cholesterol and Triglycerides Tests
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 along the inside of the artery walls, forming what is known as
plaque. Large amounts of plaque increase your chances
of having a heart attack or stroke.
-
HDL
(high-density lipoprotein) cholesterol 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)
cholesterol carries mostly fat and only a small amount of protein from the
liver to other parts of the body. It is sometimes called "bad cholesterol." A
high LDL cholesterol level may increase your chances of developing heart
disease.
-
VLDL: (very low-density
lipoprotein) cholesterol 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.
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.
Some medical experts recommend routine cholesterol and
triglyceride testing to screen for problems that affect the way cholesterol is
produced, used, carried in the blood, or disposed of by the body. Others may
choose to routinely measure only total cholesterol and HDL levels.
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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 (xanthomatosis), which may be caused by a rare genetic
disease that causes very high cholesterol levels.
How To Prepare
Preparation depends on the test. Ask your health professional which
test you are having.
- 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 health professional about all the nonprescription and prescription
medicines and herbs or natural substances you take.
Tell your health professional 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 health professional about any concerns you have
regarding the need for the test, its risks, how it will be done, or what the
results will indicate. 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.
Cholesterol and triglyceride levels vary according to your age and
sex. Results may also vary from lab to lab.
Cholesterol and
triglycerides*
|
Total cholesterol
|
Desirable:
|
|
|
Borderline high:
|
- 200–239 mg/dL
- 5.2–6.2
mmol/L
|
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High:
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- 240 mg/dL or higher
- 6.2
mmol/L or higher
|
|
HDL cholesterol
|
High (desirable):
|
- More than 60 mg/dL
- More
than 1.6 mmol/L
|
|
Acceptable:
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- 40–60 mg/dL
- 1.0–1.6
mmol/L
|
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Low (undesirable):
|
- Less than 40 mg/dL
- Less
than 1.0 mmol/L
|
|
Total cholesterol-to-HDL
ratio
|
Desirable:
|
|
|
Undesirable:
|
|
|
LDL cholesterol
|
Optimal:
|
- Less than 100 mg/dL
- Less
than 2.6 mmol/L
|
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Near optimal:
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- 100–129 mg/dL
- 2.6–3.4
mmol/L
|
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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
|
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Very high:
|
- 190 mg/dL or higher
- 4.9
mmol/L or higher
|
|
VLDL cholesterol
|
Optimal:
|
- Less than 130 mg/dL
- Less
than 3.4 mmol/L
|
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Borderline high:
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- 140–159 mg/dL
- 3.4–4.1
mmol/L
|
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High:
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- 160 mg/dL or higher
- 4.1
mmol/L or higher
|
|
Triglycerides
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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
|
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Very high:
|
- 500 mg/dL or higher
- 5.6
mmol/L or higher
|
|
*The figures in this table
are provided by the National Cholesterol Education Program (NCEP) of the
National Institutes of Health (NIH).
|
- An HDL level of 60 mg/dL (1.5 mmol/L) or
higher protects against heart disease.
- HDL cholesterol levels of 40 mg/dL (1.0 mmol/L) or lower
increase your risk of developing heart disease, especially if you also have
high total cholesterol levels.
- Very high cholesterol and
triglyceride levels may be caused by an inherited form of high cholesterol
(hypercholesterolemia or hyperlipidemia).
Many conditions can affect cholesterol and triglyceride levels.
Your health professional will talk with you about any abnormal results that may
be related to your other health problems.
What Affects the Test
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
- 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 (such as diet changes, weight loss, and
exercise) 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:
- Reducing saturated (animal) fats and
cholesterol in the diet while increasing fiber and complex
carbohydrates.
- Losing weight. An
improvement may occur if you lose as little as
5 lb (2.5 kg) to
10 lb (4.5 kg).
- Moderate consumption of alcohol can also increase
HDL cholesterol.
- Moderate alcohol consumption means no more
than 2 drinks per day for men or 1 drink per day for women; 1 drink is
12 fl oz (350 mL) of beer,
5 fl oz (150 mL) of wine, or
1.5 fl oz (45 mL) of
liquor.
- The benefits of alcohol consumption must be balanced
against the increased risk of
alcoholism,
high blood pressure, heart problems such as
atrial fibrillation and
heart failure, and cirrhosis.
- The National Cholesterol Education Program (NCEP) has developed a
risk assessment calculator to estimate your risk of having a heart attack or
dying from coronary artery disease over 10 years. This tool is designed to
estimate risk in adults age 20 and older who do not have heart disease or
diabetes. Use the
Interactive Tool: Are You at Risk for a Heart Attack?
to calculate your risk of coronary artery disease.
- Talk to your health professional about which cholesterol
screening is best for you. Medical experts disagree about routine screening for
lipid disorders.
- 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
Other Works Consulted
-
Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed.
Philadelphia: Saunders.
-
Fischbach FT, Dunning MB III, eds. (2004).
Manual of Laboratory and Diagnostic Tests, 7th ed.
Philadelphia: Lippincott Williams and Wilkins.
-
Genest J, et al. (2003). Recommendations for the
management of dyslipidemia and the prevention of cardiovascular disease:
Summary of the 2003 update. Canadian Medical Association
Journal, 169(9): 921–924. Also available online:
http://www.cmaj.ca/cgi/content/full/169/9/921/DC1.
-
Handbook of Diagnostic Tests
(2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.
-
Pagana KD, Pagana TJ (2002). Mosby’s
Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis:
Mosby.
Credits
| Author | Sydney Youngerman-Cole, RN, BSN, RNC |
| Editor | Susan Van Houten, RN, BSN, MBA |
| Associate Editor | Tracy Landauer |
| Primary Medical Reviewer | Caroline S. Rhoads, MD - Internal Medicine |
| Specialist Medical Reviewer | Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology |
| Last Updated | October 6, 2005 |
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| Author: | Sydney Youngerman-Cole, RN, BSN, RNC | Last Updated October 6, 2005 |
| Medical Review: | Caroline S. Rhoads, MD - Internal Medicine
Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology |
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