Cholesterol levels are determined through chemical analysis of a blood sample taken from a finger prick or from a vein in the arm. Home cholesterol kits, first approved in 1993, test only for total cholesterol levels but are as accurate as tests done in a doctor’s office, says Steven Gutman, M.D., director of FDA’s division of clinical laboratory devices.
“These tests can give a consumer very valuable information when screening for High cholesterol,” he says. “But they shouldn’t be considered substitutes for a test conducted in a doctor’s office.” He adds that if test results are elevated, consumers should see a doctor right away for a more refined blood analysis. The National Cholesterol Education Program considers cholesterol testing in a doctor’s office to be the preferred way because the patient can get advice immediately about the meaning of the results and what to do.
Besides determining total cholesterol levels, doctors often order a lipoprotein profile that shows the amounts of LDL, HDL, and another type of blood fat called triglycerides. This information gives doctors a better idea of heart disease risk and helps guide any treatment.
Cholesterol levels are measured in milligrams per deciliter (mg/dL). The National Cholesterol Education Program developed the following classifications for people over age 20 who do not have heart disease:
- Desirable blood cholesterol-Total blood cholesterol is less than 200 mg/dL; LDL is lower than 130 mg/dL.
- Borderline High cholesterol-Total level is between 200 and 239 mg/dL or LDL is 130 to 159 mg/dL.
- High blood cholesterol-Total level is greater than 240 mg/dL or LDL is 160 mg/dL or higher. For patients with heart disease, LDL above 100 mg/dL is too high. In addition, an HDL level less than 35 mg/dL is considered low and increases the risk of heart disease.
The main goal of cholesterol treatment is to lower LDL in people without heart disease. If the LDL level is in the “high” category and fewer than two other risk factors for heart disease are present, the goal is an LDL level lower than 160 mg/dL. If two or more risk factors are present, the goal is less than 130 mg/dL. If a patient already has heart disease, LDL levels should be 100 mg/dL or less. By reducing LDL, heart disease patients may prevent future heart attacks, prolong their lives, and slow down or even reverse cholesterol buildup in the arteries, according to the National Heart, Lung, and Blood Institute.
Revision date: July 8, 2011
Last revised: by Janet A. Staessen, MD, PhD