Non-High Density Lipoprotein Cholesterol

A non-high-density lipoprotein (non-HDL) cholesterol test determines the combined amount of cholesterols in the blood other than HDL cholesterol.

Cholesterol is a waxy substance that helps cells in the body work properly, and there are several different types of cholesterol. High-density lipoprotein (HDL) cholesterol is known as “good” cholesterol because it is associated with cardiovascular health.

Other types of cholesterol, grouped together as non-HDL cholesterol, are often thought of as “bad” cholesterol because they can accumulate in the arteries and increase the risk of heart disease, stroke, and heart attacks.

A non-HDL cholesterol test calculates the amount of these potentially dangerous types of cholesterol in a sample of blood. This calculation requires first measuring total cholesterol and HDL cholesterol. Non-HDL cholesterol is then calculated by subtracting HDL cholesterol from total cholesterol.

Purpose of the test

The purpose of a non-HDL cholesterol test is to determine the amount of “bad” cholesterol in the blood. This common way of assessing cardiovascular health is done by first measuring total cholesterol and subtracting HDL cholesterol. Non-HDL cholesterol tests can be used for screening, monitoring, and diagnosis.

Screening is checking for a health problem before there are any symptoms. Periodic cholesterol testing is often done to identify children and adults who have high levels of non-HDL cholesterol, which is associated with an elevated risk of cardiovascular problems like heart disease, heart attack, and stroke.

Monitoring is testing that is done to see how a patient’s condition has changed, including in response to treatment. People who have had abnormal cholesterol levels in the past or who have been diagnosed with cardiovascular disease may be monitored with repeated cholesterol tests over time.

Diagnosis is identifying the cause of a health problem after symptoms have started. Tests that measure cholesterol, including non-HDL cholesterol, may be part of the evaluation of patients with symptoms that are consistent with cardiovascular disease. Cholesterol may also be tested to diagnose some conditions affecting the liver, pancreas, or thyroid.

What does the test measure?

A non-HDL cholesterol test involves at least three components:

• Total cholesterol: This is a measurement of the sum of all kinds of cholesterol in a sample of blood.
• HDL cholesterol: This is a direct measurement of “good” cholesterol, which is found in high-density lipoproteins. Lipoproteins are particles made up of protein and fat that carry cholesterol in the blood.
• Non-HDL cholesterol: This is a simple calculation made by subtracting the measured amount of HDL cholesterol from the measured amount of total cholesterol.

Non-HDL cholesterol includes multiple kinds of cholesterol that can build up in the arteries and increase the risk of serious health problems. Specifically, non-HDL cholesterol encompasses low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, intermediate-density lipoprotein (IDL) cholesterol, and lipoprotein(a).

When should I get a non-high-density lipoprotein cholesterol test?

Cholesterol testing can be ordered in many different circumstances. Whether testing is appropriate for you depends on your specific situation.

There are not strict guidelines for when to perform health screenings that include cholesterol testing. The age at which to start screening and how frequently screening is repeated may depend on whether you have risk factors for cardiovascular disease. Examples of risk factors include:

• High blood pressure
• Diabetes
• Cigarette smoking
• A family history of heart disease that occurs at an early age

Your doctor can review your risk factors and describe the optimal schedule for cholesterol screening in your case. Although not all experts agree on the best schedule for cholesterol screening, many health professionals follow recommendations similar to those described in the table below:

Cholesterol screening generally involves measuring at least total cholesterol and HDL cholesterol, which allows non-HDL cholesterol to be calculated. In many cases, a full lipid panel is used for screening, which shows an estimated level of LDL cholesterol along with total cholesterol, HDL cholesterol, and another fat-like substance called triglycerides.

As a method of monitoring cardiovascular health, cholesterol tests are most frequently used if:

• You have previously been diagnosed with heart disease or another cardiovascular problem
• You have had abnormal cholesterol levels in the past, such as elevated non-HDL cholesterol
• You are making lifestyle changes and/or taking medications as a form of treatment to improve your cardiovascular health

While less often used for diagnosis, cholesterol testing might be included in the diagnostic process if you have symptoms that may be related to problems affecting the liver, thyroid, pancreas, or cardiovascular system.

Because cholesterol testing is prescribed according to many individual factors, your doctor is in the best position to address when you should have a cholesterol test that assesses non-HDL cholesterol.

How to get tested

Non-HDL cholesterol can be calculated as part of testing that measures total cholesterol and HDL cholesterol. These cholesterol tests are usually ordered by a doctor. A blood sample is required for these tests and can be taken at a medical office, laboratory, or hospital. A laboratory analyzes the sample to determine the amounts of different kinds of cholesterol in the blood.

Some cholesterol tests are performed on-site without having to send a sample to a laboratory. This is known as point-of-care testing, and it is done with a drop of blood from your fingertip. Point-of-care tests provide rapid results and may be done in hospitals, clinics, pharmacies, or events such as health fairs.

Can I take the test at home?

Cholesterol can be measured with different kinds of at-home tests, including self-tests and self-collection kits.

Self-tests involve placing a drop of blood from your fingertip onto special test paper. In most cases, that paper is then placed in a small device that determines cholesterol levels. Some self-tests use test paper that changes color based on cholesterol levels. If a self-test measures total cholesterol and HDL cholesterol, those values can be used to calculate the amount of non-HDL cholesterol.

Self-collection kits allow you to take a blood sample from your fingertip and then mail it to a laboratory for testing. Results are usually provided within a few days through an online health portal. The test may include non-HDL cholesterol, or you may be able to make this calculation yourself if total cholesterol and HDL cholesterol are analyzed.

How much does the test cost?

The cost of a non-HDL cholesterol test can vary based on factors including:

• The number of measurements included in the test
• Whether it is a laboratory or point-of-care test
• Where the test is conducted
• Whether the test is covered by health insurance

Charges can arise related to office visits, taking the test sample, and analyzing your blood. These charges may be covered by insurance, especially if your doctor prescribes the test. However, you may still have copayments or costs toward your deductible. For this reason, you should contact your health insurance plan and your doctor for more specific information on the cost of non-HDL cholesterol testing.

Non-HDL cholesterol tests are usually performed in a medical setting such as a doctor’s office, hospital, or health clinic. Laboratory testing involves a sample of blood taken from a vein that is sent to a lab, and point-of-care testing uses a fingerstick to rapidly analyze a drop of blood.

Before the test

Fasting may be required before a test of non-HDL cholesterol. Many doctors request that patients fast before cholesterol tests. Fasting is most common if the test includes an assessment of LDL cholesterol and triglycerides because these levels are more susceptible to changing based on recent food consumption.

If the test is only measuring total cholesterol and HDL cholesterol so that non-HDL cholesterol can be calculated, fasting is not usually necessary.

If you need to fast, you will need to avoid consuming any food or beverages besides water for 8 to 12 hours before the test. Many fasting blood tests are scheduled for the morning to make this fasting period easier.

Ask your doctor for specific instructions before cholesterol testing to make sure you know about whether to fast or follow any other pretest preparations.

During the test

If you are having a needle blood draw, you will be seated during the test. A nurse or technician will usually wrap an elastic band above your elbow to maximize blood flow in your veins. They will disinfect an area of your skin and then insert a needle into the vein in order to withdraw a vial of blood.

This type of blood draw is routine and normally takes less than a few minutes. You may feel a sting during the test, but this pain is typically very brief.

If you are having a point-of-care test, your fingertip will be cleaned with an antiseptic wipe, and then the nurse or technician will prick your finger with a tiny needle. One or more drops of blood will be applied to a special test paper that is used for the analysis. Any pain from the finger prick is usually minor and short-lived.

After the test

Once a blood draw is complete, a bandage or swab is placed over the puncture site to prevent bleeding. Your arm may have some bruising or pain, but more serious side effects are rare. You can return to normal activity once the blood draw is complete.

If you had to fast for the test, it may be helpful to bring a snack with you so that you have something to eat immediately after the test is over.

For a point-of-care test, there are usually no side effects or activity restrictions after the test. If your fingertip is bleeding, you may be provided with a small bandage or cotton swab so that you can apply pressure to the puncture site.

Receiving test results

Results from a laboratory cholesterol test with a needle blood draw are most often available within a few business days. You will normally be provided with a test report that is sent by mail or accessible through an electronic health portal. Your doctor may also call you or schedule an appointment to review the results.

Point-of-care tests provide rapid results, so if you have a fingerstick test, you will generally have results within a few minutes. The doctor or nurse who conducts the test may show you the result and/or review it with you.

Interpreting test results

Non-HDL cholesterol is usually listed in milligrams per deciliter (mg/dL) of blood or in millimole per liter (mmol/L). A cholesterol test report will show a separate line for each type of cholesterol that was assessed including total cholesterol, HDL cholesterol, and non-HDL cholesterol.

While some cholesterol test reports may not specifically list non-HDL cholesterol, the doctor can quickly calculate it by subtracting measured HDL cholesterol from total cholesterol. In some cases, the laboratory or your doctor may also calculate a ratio of total cholesterol to HDL cholesterol.

In addition to showing your levels, the test report will list the reference ranges for each type of cholesterol. This is important because it demonstrates what levels are considered to be normal for analyses done by that specific laboratory.

There is no single reference range for non-HDL cholesterol that is normal for all people. Instead, interpretation of non-HDL cholesterol tests accounts for factors such as:

• Your sex
• Your age
• Your health history and overall health
• Your family health history, including relatives with cardiovascular disease
• Your lifestyle factors that can affect heart health, such as smoking

A review of these factors along with your cholesterol levels can help a doctor assess your risk of cardiovascular problems like coronary heart disease. Elevated levels of non-HDL cholesterol are associated with an increased risk of cardiovascular disease.

The best way to understand the significance of a cholesterol test is to discuss the result with a doctor. A doctor can review your levels of different types of cholesterol and address what those levels mean for your health. When appropriate, the doctor can also suggest specific steps to try to reduce your risk of cardiovascular disease.

Are test results accurate?

Cholesterol testing is widely conducted to assess the risk of cardiovascular disease. Though they are widely depended on for this purpose, cholesterol tests are not 100% accurate. Some factors that can affect the accuracy of non-HDL cholesterol testing include:

• Active illness: A current infection or illness may influence blood cholesterol levels.
• Variability among individuals and labs: Stress and other individual factors may contribute to slight changes in cholesterol test results. In addition, different laboratory methods can return small variations in cholesterol levels from lab to lab.
• Some blood disorders: Although uncommon, certain blood disorders can cause HDL levels to be lower than they actually are. This can make a calculation of non-HDL cholesterol inaccurate.

The accuracy of point-of-care tests vary from brand to brand, but both laboratory tests and point-of-care tests can be used for cholesterol testing.

If you have any questions about the accuracy of a specific cholesterol test, you should raise those questions directly with the doctor who ordered the test.

Do I need follow-up tests?

If your test finds normal levels of non-HDL cholesterol and you don’t have risk factors for cardiovascular disease, you may not need any follow-up testing. Your doctor may still recommend repeating cholesterol screening every few years.

If you have abnormal non-HDL cholesterol levels, the doctor may recommend further testing to evaluate other types of cholesterol. They may also suggest other tests to assess your heart health and cardiovascular function.

Abnormal results on a point-of-care test may need to be confirmed with a follow-up test analyzed by a laboratory.

Questions for your doctor about test results

To learn more about your non-HDL cholesterol test, you can raise one or more of the following questions with your doctor:

• What kinds of cholesterol were measured on my test?
• Which, if any, cholesterol levels were abnormal?
• What other factors do you consider when determining my cardiovascular disease risk?
• Do you recommend any follow-up testing?
• Based on my non-HDL cholesterol levels, should I make any lifestyle changes or begin any treatment to improve my cardiovascular health?

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