The lipid profile is used as part of a cardiac risk assessment to help determine an individual's risk of heart disease and to help make decisions about what treatment may be best if there is borderline or high risk.

Lipids are a group of fats and fat-like substances that are important constituents of cells and sources of energy. Monitoring and maintaining healthy levels of these lipids is important in staying healthy. (For more on lipids, see the "What is being tested?" section.)

The results of the lipid profile 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 lipid-lowering medications such as statins.

A lipid profile typically includes:

• Total cholesterol — this test measures all of the cholesterol in all the lipoprotein particles.
• High-density lipoprotein cholesterol (HDL-C) — measures the cholesterol in HDL particles; often called "good cholesterol" because it removes excess cholesterol and carries it to the liver for removal.
• Low-density lipoprotein cholesterol (LDL-C) — calculates 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 profile. These parameters are calculated from the results of the tests identified 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/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 Common Questions #5 or the article on LDL Particle Testing.

Adults

It is recommended that healthy adults with no other risk factors for heart disease be tested with a fasting lipid profile once every four to six years. Initial screening may involve only a single test for total cholesterol and not a full lipid profile. However, if the screening cholesterol test result is high, it will likely be followed by testing with a lipid profile.

If other risk factors are present or if previous testing revealed a high cholesterol level in the past, more frequent testing with a full lipid profile is recommended.

Risk factors other than high low-density lipoprotein cholesterol (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

Note: High HDL (60 mg/dL or above) is considered a "negative risk factor" and its presence allows the removal of one risk factor from the total.

Youths

For children and adolescents, routine lipid testing is recommended by the American Academy of Pediatrics (AAP) in all children once between the ages of 9 and 11 and again between 17 and 21. Earlier and more frequent screening with a lipid profile is recommended for children and youths who are at an increased risk of developing heart disease as adults. 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 profile, according to the AAP.

Children younger than 2 years old are too young to be tested.

For additional details on this, see the screening articles for Children, Teens, Young Adults, Adults, and Adults 50 and Up.

Monitoring

A lipid profile may also 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 drug therapy such as statins.

Adults

In general, healthy lipid levels help to maintain a healthy heart and lower the risk of heart attack or stroke. A health practitioner will take into consideration the results of each component of a lipid profile plus other risk factors to help determine a person's overall risk of coronary heart disease, whether treatment is necessary and, if so, which treatment will best help to lower the person's risk of heart disease.

In 2002, the National Cholesterol Education Program (NCEP) Adult Treatment Panel III provided the guidelines for evaluating lipid levels and determining treatment. However, in 2013, the American College of Cardiology (ACC) and the American Heart Association (AHA) published new guidelines on treatment of cholesterol to reduce cardiovascular disease risk in adults. These guidelines recommend a treatment strategy different than those from NCEP. Decisions about cholesterol-lowering therapies are no longer focused on LDL-C or non-HDL-C targets, but are based on the 10-year risk of atherosclerotic cardiovascular disease (ASCVD) and other factors.

The latest guidelines include a newly developed, evidence-based risk calculator for ASCVD used to identify individuals most likely to benefit from therapy. It is intended for people without heart disease between the ages of 40 and 79. Many factors are considered in the calculation, including age, gender, race, total cholesterol, HDL-C, blood pressure, presence of diabetes, and smoking habit. Additionally, the updated guidelines recommend evaluating therapeutic response compared to LDL-C baseline values, with reduction thresholds differing based on the intensity of the lipid-lowering drug therapy. (For more about treatment, see Common Questions #1.)

Use of the updated risk calculator and guidelines remains controversial. Many still use the older guidelines from the NCEP Adult Treatment Panel III to evaluate lipid levels and CVD risk:

LDL Cholesterol
Optimal: Less than 100 mg/dL (2.59 mmol/L); for those with known disease (ASCVD or diabetes), less than 70 mg/dL (1.81 mmol/L) is optimal
Near/above optimal: 100-129 mg/dL (2.59-3.34 mmol/L)
Borderline high: 130-159 mg/dL (3.37-4.12 mmol/L)
High: 160-189 mg/dL (4.15-4.90 mmol/L)
Very high: Greater than 190 mg/dL (4.90 mmol/L)

Total Cholesterol
Desirable: Less than 200 mg/dL (5.18 mmol/L)
Borderline high: 200-239 mg/dL (5.18 to 6.18 mmol/L)
High: 240 mg/dL (6.22 mmol/L) or higher

HDL Cholesterol
Low level, increased risk: Less than 40 mg/dL (1.0 mmol/L) for men and less than 50 mg/dL (1.3 mmol/L) for women
Average level, average risk: 40-50 mg/dL (1.0-1.3 mmol/L) for men and between 50-59 mg/dl (1.3-1.5 mmol/L) for women
High level, less than average risk: 60 mg/dL (1.55 mmol/L) or higher for both men and women

Fasting Triglycerides
Desirable: Less than 150 mg/dL (1.70 mmol/L)
Borderline high: 150-199 mg/dL(1.7-2.2 mmol/L)
High: 200-499 mg/dL (2.3-5.6 mmol/L)
Very high: Greater than 500 mg/dL (5.6 mmol/L)

Non-HDL Cholesterol
Optimal: Less than 130 mg/dL (3.37 mmol/L)
Near/above optimal: 130-159 mg/dL (3.37-4.12mmol/L)
Borderline high: 160-189 mg/dL (4.15-4.90 mmol/L)
High: 190-219 mg/dL (4.9-5.7 mmol/L)
Very high: Greater than 220 mg/dL (5.7 mmol/L)

Unhealthy lipid levels and/or the presence of other risk factors such as age, family history, cigarette smoking, diabetes and high blood pressure, may mean that the person tested requires treatment.

The NCEP Adult Treatment Panel III guidelines uses the results of lipid tests and these other major risk factors to define target LDL cholesterol levels. According to those guidelines, if individuals have LDL-C above the target values, they will be treated.

The target LDL-C value is:

• Less than 100 mg/dL (2.59 mmol/L) if the person has 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 the person has 2 or more risk factors
• Less than 160 mg/dL (4.14 mmol/L) if the person has 0 or 1 risk factor

Youths

A full, fasting lipid panel is recommended for screening youths 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:

*Adapted from "Expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents: Summary report." Pediatrics 2011; 128.

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 profile. Beyond that, research continues into the usefulness of other non-traditional markers of cardiac risk, such as ₂Lp-PLA. A health 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.