Most adults have probably had their total cholesterol measured, but as evidence continues to emerge about the different roles played by the different lipoproteins, we realize more and more how important it is to measure each lipoprotein separately.

It’s now recommended that everyone over age twenty should get a fasting lipid profile every five years. A fasting lipid profile measures your LDL, HDL, and triglyceride levels, not just your cholesterol level. Most of the time, you can get this test at your primary care doctor’s office.

As the name suggests, to prepare for the test, you need to fast. Avoiding alcohol for twenty-four hours and not eating for twelve hours before your appointment allow the doctor to get an accurate reading of your lipoproteins.

Triglyceride levels can fluctuate widely in some people depending on the food they eat, so it is a good idea to eat what you’d typically eat in the week or two before getting a lipid test. Triglyceride levels are also significantly elevated in the hours after eating a meal that contains any fat, which is why it is important to fast for twelve hours.

Your LDL cholesterol level is almost always calculated using a formula that depends on the accurate measurement of a fasting triglyceride level, so if you couldn’t resist that doughnut before your appointment, your triglyceride and LDL levels will be inaccurate. The fasting is probably the most difficult part of the full cholesterol profile for most patients.

Once you get to your doctor’s office, someone will draw a tube’s worth of blood and you’re all done! Behind the scenes, the lab technician puts your blood into an automated chemical analyzer and runs the various lipid tests rapidly. If your triglyceride level is greater than 400, the lab can’t calculate your LDL value.

In more sophisticated labs, additional tests can be done to determine the LDL in that situation, but these require more costly and time-consuming procedures that are not always available. If that’s the case, your doctor may send your blood to a national lab.

LDL cholesterol can be measured directly by several different methods, each of which has its advantages and disadvantages, but all of which are more expensive than simply calculating LDL cholesterol from a standard lipid profile. So, if your LDL cholesterol can be determined by calculation.

That is the preferred method and the one used in virtually all of the major cholesterol-lowering trials. In addition to drawing your blood work, your doctor will perform a physical examination that can determine if you have other risk factors that will increase your likelihood of developing coronary disease.

Typically, this involves measuring your blood pressure and checking your pulse to ensure that your heartbeat is regular and forceful. Sometimes your doctor will feel the thyroid gland in your neck to determine its size, as an under- or overactive thyroid can affect blood lipid levels.

He or she may also feel the pulses of the carotid arteries in your neck and listen to blood flow through those arteries to ensure there are no blockages there. To assess your heart and cardiovascular function in more detail, most doctors will listen to your heart sounds and feel the pulses in your legs.

Which can be lost if there are significant blockages in any of the arteries that lead to the feet. If your doctor finds anything abnormal, you generally will get further laboratory testing or imaging procedures. These could include an electrocardiogram (EKG), chest x-ray, echocardiogram (sound wave picture of the heart), or tests of thyroid or kidney function.

Reduced pulses in the legs are often assessed by Doppler (sound wave) measurements or an equivalent noninvasive test. When these studies are completed and the lipid profile result has come back, your doctor is armed with the information needed to make recommendations about treating your lipid levels.