A lipid profile or lipid panel is a panel of

blood test A blood test is a medical laboratory, laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose ...

s used to find abnormalities in

blood lipid Blood lipids (or blood fats) are lipids in the blood, either free or bound to other molecules. They are mostly transported in a phospholipid capsule, and the type of protein embedded in this outer shell determines the fate of the particle and its ...

( such as

cholesterol Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all anima ...

and

triglyceride A triglyceride (from '' tri-'' and '' glyceride''; also TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and other vertebrates ...

s) concentrations. The results of this test can identify certain

genetic diseases A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders are ...

and can determine approximate risks for

cardiovascular disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...

, certain forms of

pancreatitis Pancreatitis is a condition characterized by inflammation of the pancreas. The pancreas is a large organ behind the stomach that produces digestive enzymes and a number of hormone A hormone (from the Ancient Greek, Greek participle , "se ...

, and other diseases. Lipid panels are usually ordered as part of a

physical exam In a physical examination, medical examination, clinical examination, or medical checkup, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions ...

, along with other panels such as the

complete blood count A complete blood count (CBC), also known as a full blood count (FBC) or full haemogram (FHG), is a set of medical laboratory tests that provide cytometry, information about the cells in a person's blood. The CBC indicates the counts of white blo ...

(CBC) and basic metabolic panel (BMP).

Components

A lipid profile report typically includes: *

Low-density lipoprotein Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall density ...

(LDL) *

High-density lipoprotein High-density lipoprotein (HDL) is one of the five major groups of lipoproteins. Lipoproteins are complex particles composed of multiple proteins which transport all fat molecules (lipids) around the body within the water outside cells. They are t ...

(HDL) * Total

s * Total

LDL is not usually actually measured, but calculated from the other three using the ''Friedewald equation''. A laboratory can optionally calculate the two extra values from the report: *

Very low-density lipoprotein Very-low-density lipoprotein (VLDL), density relative to extracellular water, is a type of lipoprotein made by the liver. VLDL is one of the five major groups of lipoproteins (chylomicrons, VLDL, intermediate-density lipoprotein, LDL, low-density ...

(VLDL) * Cholesterol:HDL ratio

Procedure and indication

Recommendations for cholesterol testing come from the Adult Treatment Panel (ATP) III guidelines, and are based on many large clinical studies, such as the

Framingham Heart Study The Framingham Heart Study is a long-term, ongoing cardiovascular cohort study of residents of the city of Framingham, Massachusetts. The study began in 1948 with 5,209 adult subjects from Framingham, and is now on its third generation of partic ...

. For healthy adults with no cardiovascular risk factors, the ATP III guidelines recommend screening once every five years. A lipid profile may also be ordered at regular intervals to evaluate the success of lipid-lowering drugs such as

statin Statins (or HMG-CoA reductase inhibitors) are a class of medications that lower cholesterol. They are prescribed typically to people who are at high risk of cardiovascular disease. Low-density lipoprotein (LDL) carriers of cholesterol play ...

s. In the pediatric and adolescent population, lipid testing is not routinely performed. However, the

American Academy of Pediatrics The American Academy of Pediatrics (AAP) is the largest professional association of pediatricians in the United States. It is headquartered in Itasca, Illinois, and maintains an office in Washington, D.C. The AAP has published hundreds of poli ...

and the

National Heart, Lung, and Blood Institute The National Heart, Lung, and Blood Institute (NHLBI) is the third largest Institute of the National Institutes of Health, located in Bethesda, Maryland, United States. It is tasked with allocating about $3.6 billion in FY 2020 in tax revenue t ...

(NHLBI) recommend that children aged 9–11 be screened once for severe cholesterol abnormalities. This screening can be valuable to detect

such as

familial hypercholesterolemia Familial hypercholesterolemia (FH) is a genetic disorder characterized by high cholesterol levels, specifically very high levels of low-density lipoprotein cholesterol (LDL cholesterol), in the blood and early cardiovascular diseases. The mos ...

that can be lethal if not treated early. Traditionally, most laboratories have required patients to fast for 9–12 hours before screening. However, studies have questioned the utility of

fasting Fasting is the act of refraining from eating, and sometimes drinking. However, from a purely physiological context, "fasting" may refer to the metabolic status of a person who has not eaten overnight (before "breakfast"), or to the metabolic sta ...

before lipid panels, and some diagnostic labs routinely accept non-fasting samples.

Methods

Friedewald

Typically the laboratory measures only three quantities: total cholesterol; HDL; Triglycerides. A typical procedure used by NHANES 2004 uses the following measurement methods: * Total cholesterol is measured using a mixture of enzymes. First an esterase converts cholesterol esters into cholesterol and free fatty acid. Then an oxidase oxidizes the cholesterol, producing a H₂O₂ side-product that changes the color of a dye. The amount of oxidation can be precisely quantified by light absorbance at 500 nm. * Triglyceride concentration is also measured using an enzyme mixture. A lipase releases

glycerol Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

from the molecules, which gets oxidized by another enzyme while producing H₂O₂. The same color-change follows. * HDL is measured in two steps. First a special reagent is added to the serum that binds apoB-containing lipoprotein particles, shielding them from the enzymes in the next step. Then a mixture of PEGylated enzymes is added with dye. The chemical reaction is the same as the total cholesterol measurement, except that the enzymes are blocked from acting on non-HDL lipoproteins by the reagent and their own PEG tails. From these three data LDL may be calculated. According to Friedewald's equation:
''cited in'' * DL otal cholesterol− DL− Other calculations of LDL from those same three data have been proposed which yield some significantly different results. VLDL can be defined as the total cholesterol that is neither HDL nor LDL. With that definition, Friedewald's equation yields: * LDL The alternative calculations mentioned above may yield significantly different values for VLDL. The Friedewald method is reasonably reliable for the majority of patients, but is notably inaccurate in patients with

hypertriglyceridemia Hypertriglyceridemia is the presence of high amounts of triglycerides in the blood. Triglycerides are the most abundant fatty molecule in most organisms. Hypertriglyceridemia occurs in various physiologic conditions and in various diseases, and ...

(> 400 mg/dL or 4.5 mmol/L). It also underestimates LDL-C in patients with low LDL-C (< 25 mg/dL or 0.6 mmol/L). It does not take into account

intermediate-density lipoprotein Intermediate-density lipoproteins (IDLs) belong to the lipoprotein particle family and are formed from the degradation of very low-density lipoproteins as well as high-density lipoproteins. IDL is one of the five major groups of lipoproteins (chylo ...

. A "Martin/Hopkins" variation that takes into how triglycerides-to-VLDL ratio tends to vary with other parameters appears more reliable and accurate.

All-direct

Every part of the lipid panel can be measured directly using ultracentrifugation, which is the

gold standard A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...

. This type of measurement involves no errors from estimation and can also measure IDL-C and Lp(a)-C levels. Fully direct measurement is more costly, however. Laboratories may also use proprietrary tests for "direct chemical LDL-C" which require no prior separation by centrifugation. These tests are not yet standardized in US and Europe and lack validation. A specific version of the test seems popular in Japan, however. A number of other LDL-C determination methods have been used in the past or have been proposed for future use.

Implications

This test is used to identify

dyslipidemia Dyslipidemia is a metabolic disorder characterized by abnormally high or low amounts of any or all lipids (e.g. fats, triglycerides, cholesterol, phospholipids) or lipoproteins in the blood. Dyslipidemia is a risk factor for the development of ...

(various disturbances of cholesterol and triglyceride levels), many forms of which are recognized risk factors for

and rarely

. A total cholesterol reading can be used to assess an individual's risk for heart disease; however, it should not be relied upon as the only indicator. The individual components that make up total cholesterol reading— LDL, HDL, and

VLDL Very-low-density lipoprotein (VLDL), density relative to extracellular water, is a type of lipoprotein made by the liver. VLDL is one of the five major groups of lipoproteins (chylomicrons, VLDL, intermediate-density lipoprotein, LDL, low-density ...

—are also important in measuring risk. For instance, someone's total cholesterol may be high, but this may be due to very high HDL ("good cholesterol") cholesterol levels,—which can help prevent heart disease (the test is mainly concerned with high LDL, or "bad cholesterol" levels). So, while a high total cholesterol level may help give an indication that there is a problem with cholesterol levels, the components that make up total cholesterol should also be measured.

Lipid Profiling in Diabetes Risk Prediction

A study by King's College London identified a novel blood test using lipid profiling to predict diabetes risk in children. Researchers found that lipid molecules in blood plasma could serve as early indicators for metabolic diseases, including type 2 diabetes, liver disease, and heart complications, even independent of obesity levels.