Lipid profile or lipid panel is a panel of blood tests that serves as an initial broad medical screening tool for abnormalities in lipids, such as cholesterol and triglycerides. The results of this test can identify certain genetic diseases and can determine approximate risks for cardiovascular disease, certain forms of pancreatitis, and other diseases.
The lipid profile typically includes:
Using these values, a laboratory may also calculate:
- Very low-density lipoprotein (VLDL)
- Cholesterol:HDL ratio
The lipid profile tests are of 7 types:
- Total lipids
- Serum total cholesterol
- serum HDL cholesterol
- Total cholesterol/HDL cholesterol ratio
- Serum triglycerides
- serum Phospholipids
- Electrophoretic fractionation to determination percentage of
(a) Chylomicrons (b) LDL-low density lipoprotein (c) VLDL- very low density (d)HDL-high density
Procedure and indication
Current 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.
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 statins.
In the pediatric and adolescent population, lipid testing is not routinely performed. However, the American Academy of Pediatrics and NHLBI now recommend that children aged 9–11 be screened once for severe cholesterol abnormalities. This screening can be valuable to detect genetic diseases such as familial hypercholesterolemia that can be lethal if not treated early.
Traditionally, most laboratories have required patients to fast for 9–12 hours before screening. However, recent studies have questioned the utility of fasting before lipid panels, and some diagnostic labs now routinely accept non-fasting samples.
VLDL may be calculated using the Friedewald's equation:
- VLDL = Triglycerides/5
- VLDL = Total cholesterol – (HDL + LDL)
This test is used to identify hyperlipidemia (various disturbances of cholesterol and triglyceride levels), many forms of which are recognized risk factors for cardiovascular disease and rarely pancreatitis.
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—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 actually 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.
- National Cholesterol Education Program (Ncep) Expert Panel On Detection, E. (2002). "Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report". Circulation 106 (25): 3143–3421. PMID 12485966.
- "Pediatric Cardiovascular Risk Reduction Guidelines - NHLBI, NIH".
- Sidhu, D.; Naugler, C. (2012). "Fasting Time and Lipid Levels in a Community-Based Population<subtitle>A Cross-sectional Study</subtitle><alt-title>Fasting Time and Lipid Levels</alt-title>". Archives of Internal Medicine 172 (22): 1–4. doi:10.1001/archinternmed.2012.3708. PMID 23147400.
- Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18:499-502. (Cited in: Clin. Chem. 1990; 36:15-19).
- Lipid Profile: At a glance at Labtestsonline.org
- Total Cholesterol - What Are Total Cholesterol Levels? at About.com
- Friedewald’s equation for calculating VLDL and LDL at Cardiophile.org