High cholesterol is a major risk factor for coronary heart disease, heart attack and stroke, according to the American Heart Association. An accurate cholesterol test is important for identifying risk level.
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Eating or drinking before the blood test can cause a result that is artificially high.
Certain drugs can also cause a false high reading. Because of this, your health care provider may ask you to avoid food and drink, and discontinue medications before the test.
Food and Drink
The National Cholesterol Education Program (NCEP) of the National Heart, Lung and Blood Institute has determined that a total cholesterol level of less than 200 mg/dL is desirable, a low-density lipoprotein (LDL) "bad" cholesterol level of less than 100 mg/dL is optimal and a high-density lipoprotein (HDL) "good" cholesterol level of 60 mg/dL and above is protective against heart disease.
Any food or drink other than water (including coffee, tea and soft drinks) consumed within 9 to 12 hours of a cholesterol test can affect blood cholesterol. Specifically, food and drink can raise the LDL cholesterol level in the blood, causing a false high measurement above these established levels.
If you fail to fast as instructed prior to the blood test, only the values for total cholesterol and HDLwill be usable. A repeat test will be needed to determine true total and LDL cholesterol.
Several drugs can affect cholesterol measurements and cause false high results, according to the National Heart, Lung and Blood Institute. These include adrenocorticotropic hormone (ACTH), anabolic steroids, beta-adrenergic blocking agents (beta-blockers), birth control pills, corticosteroids, phenytoin, sulfonamides, thiazide diuretics and vitamin D.
Ask Your Doctor
Obtain specific instructions on preventing a false high cholesterol measurement from your health care provider before the test. Consult with your physician before discontinuing any medication, regardless if it affects blood cholesterol, because the risks of discontinuing treatment could outweigh the benefits of obtaining an accurate cholesterol measurement.