Fasting before a cholesterol test might soon become a thing of the past. Not only are there a variety of tests that do not require fasting, the need to fast for the more traditional method has been called into question by a recent study published in the Journal of the American Medical Association. It's important to ask your doctor which test is right for you and whether or not it's necessary for you to fast.
Types of Cholesterol Tests
There are several different types of cholesterol tests, and which test you take will determine whether or not you even need to think about fasting. The only type of cholesterol test that might require fasting, but which also happens to be the most common and most useful, is the low-density lipoprotein, or LDL, test. Tests for total cholesterol or high-density lipoprotein, or HDL, do not require fasting. Some tests that directly measure LDL, and therefore do not require fasting, have also become popular in some states.
Fasting
If your doctor advises you to fast prior to your cholesterol test, you should stop drinking alcohol at least 24 hours prior to your cholesterol test. You can eat up to 12 hours before the test. Once you're within 12 hours of the test, you should only drink water until after the blood is drawn.
Reasons for Fasting
Until very recently, it has been widely believed that triglyceride levels in your blood could fluctuate 20 to 30 percent after a meal. According to Harvard Medical School, the traditional way of calculating LDL, the bad cholesterol, was to subtract HDL and triglycerides from a measure of total cholesterol. The difference would be your LDL level, but if the triglyceride level was off, the results would be unreliable. A study published in 2009, however, has confirmed tests that directly measure LDL are reliable and make measurement of triglycerides, and therefore fasting, irrelevant. In addition, a researcher at the University of North Carolina Chapel Hill speculates that even if triglyceride levels fluctuate after eating, LDL test results without fasting might be a better predictor of coronary disease.
