Screening when no risk factors present: for adults, every four to six years; for children, teens and young adults, once between the ages of 9 and 11 and again between ages 17 and 21
Monitoring: at regular intervals when you have risk factors, when prior results showed high risk levels, and/or to monitor effectiveness of treatment
A blood sample is obtained by inserting a needle into a vein. Sometimes a drop of blood is collected by puncturing the skin on a fingertip. This fingerstick sample is typically used when a lipid panel is being measured on a portable testing device, for example, at a health fair.
Typically, fasting for 9-12 hours (drinking water only) before having your blood drawn is required, but some healthcare practitioners allow non-fasting lipid testing. In particular, children, teens and young adults (ages 2 to 24) may have testing done without fasting. Follow any instructions you are given and tell the person drawing your blood whether or not you have fasted.
Lipids are a group of fats and fat-like substances that are important constituents of cells and sources of energy. A lipid panel measures the level of specific lipids in the blood.
Two important lipids, cholesterol and triglycerides, are transported in the blood by lipoproteins (also called lipoprotein particles). Each type of lipoprotein contains a combination of cholesterol, triglyceride, protein, and phospholipid molecules. The particles measured with a lipid panel are classified by their density into high-density lipoproteins (HDL), low-density lipoproteins (LDL), and very low-density lipoproteins (VLDL).
A lipid panel typically includes:
- Total cholesterol—measures all the cholesterol in all the lipoprotein particles
- High-density lipoprotein cholesterol (HDL-C)—measures the cholesterol in HDL particles; often called "good cholesterol" because HDL-C takes up excess cholesterol and carries it to the liver for removal.
- Low-density lipoprotein cholesterol (LDL-C)—calculates or measures the cholesterol in LDL particles; often called "bad cholesterol" because it deposits excess cholesterol in walls of blood vessels, which can contribute to atherosclerosis. Usually, the amount of LDL-C is calculated using the results of total cholesterol, HDL-C, and triglycerides.
- Triglycerides—measures all the triglycerides in all the lipoprotein particles; most is in the very low-density lipoproteins (VLDL).
Some other information may be reported as part of the lipid panel. These parameters are calculated from the results of the tests listed above.
- Very low-density lipoprotein cholesterol (VLDL-C)—calculated from triglycerides/5; this formula is based on the typical composition of VLDL particles.
- Non-HDL-C—calculated from total cholesterol minus HDL-C
- Cholesterol/HDL ratio—calculated ratio of total cholesterol to HDL-C
An extended profile (or advanced lipid testing) may also include low-density lipoprotein particle number or concentration (LDL-P). This test measures the number of LDL particles, rather than measuring the amount of LDL-cholesterol. It is thought that this value may more accurately reflect heart disease risk in certain people. (For more, see the article on LDL Particle Testing).
Monitoring and maintaining healthy levels of these lipids is important in staying healthy. While the body produces the cholesterol needed to function properly, the source for some cholesterol is the diet. Eating too much of foods that are high in saturated fats and trans unsaturated fats (trans fats) or having an inherited predisposition can result in a high level of cholesterol in the blood. The extra cholesterol may be deposited in plaques on the walls of blood vessels. Plaques can narrow or eventually block the opening of blood vessels, leading to hardening of the arteries (atherosclerosis) and increasing the risk of numerous health problems, including heart disease and stroke.
A high level of triglycerides in the blood is also associated with an increased risk of developing cardiovascular disease (CVD), although the reason for this is not well understood.
How is the test used?
The lipid panel is used as part of a cardiac risk assessment to help determine your risk of heart disease and to help make decisions about what treatment may be best if you have borderline risk, intermediate risk, or high risk. Initial screening may involve only a single test for total cholesterol and not a full lipid panel. However, if the screening cholesterol test result is high, it will likely be followed by testing with a lipid panel.
The results of the lipid panel are considered along with other known risk factors of heart disease to develop a plan of treatment and follow-up. Depending on the results and other risk factors, treatment options may involve lifestyle changes such as diet and exercise or medications that lower lipid levels, typically statins.
Additionally, a lipid panel may be used to monitor whether treatment has been effective in lowering cholesterol levels.
When is it ordered?
Adults with no other risk factors for heart disease should be tested with a fasting lipid panel once every four to six years.
If you have risk factors or if previous testing showed that you had a high cholesterol level, more frequent testing with a full lipid panel is recommended.
Examples of risk factors other than high LDL-C include:
- Cigarette smoking
- Being overweight or obese
- Unhealthy diet
- Being physically inactive—not getting enough exercise
- Age (if you are a male 45 years or older or a female 50-55 years or older)
- Hypertension (blood pressure of 140/90 or higher or taking high blood pressure medications)
- Family history of premature heart disease (heart disease in a first-degree male relative under age 55 or a first-degree female relative under age 65)
- Pre-existing heart disease or already having had a heart attack
- Diabetes or prediabetes
Children, teens, and young adults (ages 2 to 24 years old) with no risk factors should have a lipid panel once between the ages of 9 and 11 and again between 17 and 21, according to the American Academy of Pediatrics (AAP).
Children, teens, and young adults with an increased risk of developing heart disease as adults should have earlier and more frequent screening with lipid panels. Some of the risk factors are similar to those in adults and include a family history of heart disease or health problems such as diabetes, high blood pressure, or being overweight. High-risk children should be tested between 2 and 8 years old with a fasting lipid panel, according to the AAP.
Children younger than 2 years old are too young to be tested.
A lipid panel may be ordered at regular intervals to evaluate the success of lipid-lowering lifestyle changes such as diet and exercise or to determine the effectiveness of medication such as statins.
What does the test result mean (adults)?
In general, healthy lipid levels help to maintain a healthy heart and lower the risk of heart attack or stroke. Your healthcare practitioner will take into consideration the results of each component of a lipid panel plus other risk factors to help determine your overall risk of coronary heart disease, whether treatment is necessary and, if so, which treatment will best help to lower your risk of heart disease.
Health organizations have different recommendations for treatment based on your predicted CVD risk.
Guidelines from the American College of Cardiology (ACC) and the American Heart Association (AHA) recommend that a risk calculator be used to determine your 10-year risk of CVD if you are age 40 to 75 and do not have heart disease. Many factors are considered in the calculation, including total cholesterol, LDL-C, HDL-C, age, gender, race, blood pressure, presence of diabetes, and smoking habit. An initial (baseline) risk should be calculated and then your risk can be tracked over time with each subsequent risk calculation. Ten-year risk is categorized below:
Calculated 10-Year Risk Risk Category Less than 5% Low 5% to 7.4% Borderline 7.5% to 19.9% Intermediate Greater than 20% High
ACC and AHA recommend treatment with statins if you:
- Have heart disease (diagnosed by medical history, physical exam, imaging scans, etc.)
- Have LDL-C greater than 190 mg/dL (4.90 mmol/L)
- Are age 40 to 75 years with diabetes and LDL-C 70-189 mg/dL (1.81-4.90 mmol/L) but do not have heart disease
- Are age 40 to 75 years old and do not have diabetes or heart disease but have LDL-C level between 70-189 mg/dL (1.81-4.90 mmol/L) and 10-year risk of developing heart disease of greater than 7%
The U.S. Preventive Services Task Force (USPSTF) makes recommendations on the use of statins for treatment in adults ages 40 to 75 with no history of heart disease (i.e., no symptoms of coronary artery disease or stroke), based on risk factors (i.e., LDL-C greater than 130 mg/dL(3.37 mmol/L), HDL-C level less than 40 mg/dL(1.0 mmol/L), diabetes, high blood pressure, smoking) and the use of the risk calculator.
- If you have one or more risk factors and a calculated 10-year CVD event risk of 10% or greater, USPSTF recommends the use of a low-to-moderate dose statin.
- If you have one or more risk factors and your calculated 10-year CVD event risk is 7.5% to 10%, then the Task Force says your healthcare practitioner may choose to offer a low-to-moderate dose statin. This is because the probability that you will have a CVD event is lower, so the benefit of statin is likely to be smaller.
In adults ages 21 to 39, there is not enough evidence on the effect of screening for unhealthy lipid levels, according to the USPSTF. Also, in adults 76 years or older with no history of CVD, current evidence is insufficient to assess the balance of benefits and harms of preventive statin use.
Use of the risk calculator and ACC/AHA guidelines remains controversial and is evolving as more data become available. Some say that the current risk calculator can overestimate risk. Many still use older guidelines (2002) from the NCEP Adult Treatment Panel III to evaluate lipid levels and CVD risk, as summarized in the table below:
Test Optimal or Desirable Near/Above Optimal Borderline High High Very High LDL Cholesterol Less than 100 mg/dL (2.59 mmol/L); with CVD or diabetes: less than 70 mg/dL (1.81 mmol/L) 100-129 mg/dL (2.59-3.34 mmol/L) 130-159 mg/dL (3.37-4.12 mmol/L) 160-189 mg/dL(4.15-4.90 mmol/L) Greater than 190 mg/dL (4.90 mmol/L) Total Cholesterol Less than 200 mg/dL (5.18 mmol/L) 200-239 mg/dL (5.18 to 6.18 mmol/L) 240 mg/dL (6.22 mmol/L) or higher Fasting Triglycerides Less than 150 mg/dL (1.70 mmol/L) 150-199 mg/dL(1.7-2.2 mmol/L) 200-499 mg/dL (2.3-5.6 mmol/L) Greater than 500 mg/dL (5.6 mmol/L) Non-HDL Cholesterol Less than 130 mg/dL (3.37 mmol/L) 130-159 mg/dL (3.37-4.12mmol/L); 160-189 mg/dL (4.15-4.90 mmol/L) 190-219 mg/dL (4.9-5.7 mmol/L) Greater than 220 mg/dL (5.7 mmol/L) HDL Cholesterol Low Level, Increased Risk Average Level, Average Risk High Level, Less than Average Risk Women Less than 50 mg/dL (1.3 mmol/L) 50-59 mg/dl (1.3-1.5 mmol/L) 60 mg/dL (1.55 mmol/L) or higher Men Less than 40 mg/dL (1.0 mmol/L) 40-50 mg/dL (1.0-1.3 mmol/L) 60 mg/dL (1.55 mmol/L) or higher
According to NCEP Adult Treatment Panel III guidelines, if you have LDL-C above the following target values and risk factors (e.g., family history, cigarette smoking, diabetes, high blood pressure), you require treatment.
The target LDL-C value is:
- Less than 100 mg/dL (2.59 mmol/L) if you have heart disease or diabetes [and ideally less than 70 mg/dL (1.81 mmol/L)]
- Less than 130 mg/dL (3.37 mmol/L) if you have 2 or more risk factors
- Less than 160 mg/dL (4.14 mmol/L) if you have 0 or 1 risk factor
What does the test result mean (children, teens and young adults)?
A full, fasting lipid panel is recommended for screening children and teens with risk factors for developing heart disease, according to the American Academy of Pediatrics. Fasting prior to lipid screening in children without risk factors is unnecessary. Non-high-density lipoprotein cholesterol (non-HDL-C) is the recommended test for non-fasting lipid screening. Non-HDL-C-is calculated by testing for total cholesterol and HDL-C and taking the difference between the two levels. Recommended cut-off values include:
Test Acceptable (mg/dL) Borderline (mg/dL) High (mg/dL) Children and Teens (ages 2 to 18) Total Cholesterol Less than 170 170-199 Greater than or equal to 200 Non-HDL Cholesterol Less than 120 120-144 Greater than or equal to 145 Young Adults (ages 19 to 24) Total Cholesterol Less than 190 190-224 Greater than or equal to 225 Non-HDL Cholesterol Less than 150 150-189 Greater than or equal to 190
*Adapted from "Expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents: Summary report." Pediatrics 2011; 128.
What treatments are recommended if I have unhealthy lipid levels?
Maintaining a healthy lifestyle is an important part of heart health and in treating high cholesterol. This may mean you will need to change your lifestyle, specifically by adopting a diet low in saturated fat and trans unsaturated fats (trans fats), avoiding smoking, controlling high blood pressure and diabetes, and participating in moderate exercise. You may be referred to a dietician for advice in making dietary changes.
Your healthcare practitioner will talk to you about risks and benefits of statin drug therapy, based on your history, health risks, the results of your LDL-C test, and possibly your calculated risk for CVD. Statins are generally recommended as a first choice for lowering LDL-C. You may be prescribed one of these. Your LDL-C will be checked at regular intervals to make sure that the drug is working. If the drug does not lower your LDL-C, your healthcare practitioner may increase the amount of drug or possibly add a second drug.
What is the difference between primary CVD treatment and secondary treatment?
Primary treatment is preventive. It is intended to help reduce your risk of having a first cardiovascular event (such as a heart attack or stroke). There are potential benefits – helping to prevent CVD from developing – but also potential risks/harms associated with taking statins or other lipid-lowering medications long-term. You and your healthcare practitioner need to weigh those benefits and risks.
Secondary treatment is therapy that is given when you have had a cardiovascular event or have been diagnosed with CVD. It will still likely involve statins (and/or other therapies) but is intended to help prevent another CVD event.
I had a screening test for cholesterol. It was less than 200 mg/dL (5.18 mmol/L). Do I need a lipid panel?
What is a direct LDL cholesterol test?
Most often, LDL cholesterol is calculated from the other lipid measurements in a lipid panel. However, the calculation is not valid if triglycerides are over 400 mg/dL (4.52 mmol/L). When triglycerides are over 400 mg/dL (4.52 mmol/L), LDL-C may be measured directly (direct LDL) or with special testing techniques (e.g., a beta-quantification test).
Can I test my lipids at home?
There are tests available to use at home to measure total cholesterol. You prick your finger and put blood on a piece of paper that will change color based on your cholesterol level (or use your blood and a small device to do the same thing).
There are also kits available that have you collect a blood sample at home and then mail it to a reference laboratory, which will then perform a lipid panel and send the results back to you.
Is there anything else I should know?
There is increasing interest in measuring triglycerides in people who have not fasted. The reason is that a non-fasting sample may be more representative of the "usual" circulating level of triglyceride since most of the day, blood lipid levels reflect post-meal (post-prandial) levels rather than fasting levels. However, it is not yet certain how to interpret non-fasting levels for evaluating risk, so at present there is no change in the current recommendations for fasting prior to tests for lipid levels.
A routine cardiac risk assessment typically includes a fasting lipid panel. Beyond that, research continues into the usefulness of other non-traditional markers of cardiac risk, such as high-sensitivity C-reactive protein (hs-CRP), lipoprotein A (Lp(a)), Lp-PLA2, LDL particle testing (LDL-P), apolipoprotein A-1 and apolipoprotein B. A healthcare practitioner may choose to evaluate one or more of these markers to help determine someone's risk, but there is no consensus on their use and they are not widely available. For a more detailed discussion on these, see the article on Cardiac Risk Assessment.