Common Questions
1. I had a screening test for cholesterol. It was less than 200 mg/dL (5.18 mmol/L). Do I need a lipid profile?
If your total cholesterol is below 200 (5.18 mmol/L) and you have no family history of heart disease or other risk factors a full lipid profile is probably not necessary. However, an HDL-cholesterol measurement would be advisable to assure that you do not have a low HDL. Many screening programs now offer both cholesterol and HDL. If total cholesterol is below 200 (5.18 mmol/L) and HDL is above 40 (1.04 mmol/L), a lipid profile is not recommended.
2. Do I need to fast before having a lipid profile performed?
Yes. For 12 to 14 hours before the test, only water is allowed.
3. How often do I need a lipid profile test?
Recommendations are for healthy individuals with no other risks of heart disease to be screened for cholesterol and HDL every five years. You do not need to have a full lipid profile. However, if you have other risk factors or have had a high cholesterol in the past, you should be tested more regularly and you should have a full lipid profile.
4. My lipid profile results came back with high triglycerides and no LDL-cholesterol. Why?
In most screening lipid profiles, LDL-cholesterol is calculated from the other lipid measurements. However, the calculation is not valid if triglycerides are over 400 mg/dL (4.52 mmol/L). To determine LDL-cholesterol when triglycerides are over 400 mg/dL (4.52 mmol/L) requires special testing techniques such as a direct LDL test or a lipid ultracentrifugation test (sometimes called a beta-quantification test).
5. What is VLDL?
Very Low Density Lipoprotein (VLDL) is one of three major lipoprotein particles. The other two are high density lipoprotein (HDL) and low density lipoprotein (LDL). Each one of these particles contains a mixture of cholesterol, protein, and triglyceride, but in varying amounts unique to each type of particle. LDL contains the highest amount of cholesterol. HDL contains the highest amount of protein. VLDL contains the highest amount of triglyceride. Since VLDL contains most of the circulating triglyceride and since the compositions of the different particles are relatively constant, it is possible to estimate the amount of VLDL cholesterol by dividing the triglyceride value (in mg/dL) by 5. At present, there is no simple, direct way of measuring VLDL-cholesterol, so the estimate calculated from triglyceride is used in most settings. This calculation is not valid when the triglyceride is greater than 400 mg/dl (see question 3 above).
