What is cholesterol?
Cholesterol is a naturally occurring body chemical that helps handles dietary fats. Three fats are commonly measured in the lipid profile:
- Low-density cholesterol (LDL)- or "bad" cholesterol
Too much LDL causes fatty "plaques" to form inside artery walls, causes hardening of the arteries, obstructs blood flow to the heart and other organs, and may lead to heart disease and stroke.
- High-density cholesterol (HDL)- or "good" cholesterol
HDL can carry away LDL cholesterol, prevent a build-up of plaque, keep the arteries open and keep blood flowing freely to important organs such as the heart and brain.
These are fats that your body stores. Some triglycerides circulate in the blood to provide energy for muscles. After a meal rich in fats, the triglyceride levels rises very high as dietary fats are sent from the gut to fat tissue for storage. Triglyceride testing MUST NOT be performed after eating and should only be performed after an 8-12 hour (overnight) fast.
Another test, Total cholesterol, is a measure of the total cholesterol content of your blood. This is the ONLY test we will run on your blood at each donation.
These four tests - LDL, HDL, Triglycerides and Total Cholesterol - comprise the lipid profile used in determining your risk of cardiovascular disease. Test measurements, however, are only part of the picture. Additional considerations include exercise, smoking, family risk and other factors. Only your physician can tell you what your lipid profile means and put it in perspective with your personal and family health history.
Do I need to be fasting for these tests to be done?
You must be fasting to measure triglycerides, LDL and HDL accurately. Since we will not be testing for triglyceride, LDL or HDL, you do NOT need to be fasting. The only test we perform, the Total Cholesterol level, does not change in response to a single meal. In fact, it takes several weeks of a dietary change to see any change in your total cholesterol level.
What other factors can affect cholesterol measurement?
Total Cholesterol should be measured when a person is healthy. Cholesterol is low during acute illness and periods of stress; you should wait at least 6 weeks after illness to have cholesterol measured.
Cholesterol is high during pregnancy; cholesterol levels measured within 6 weeks of conclusion of a pregnancy may not be accurate.
Beta blockers, epinephrine, oral contraceptives and vitamin D can affect cholesterol levels.
Since many factors can affect cholesterol, your Total Cholesterol level has more meaning when followed over time to see if the level is changing. Doctors follow cholesterol levels on patients who have been prescribed diets or drugs to see how well those measures are working.
What is a desirable cholesterol level?
Only your physician can correctly interpret your cholesterol results. This interpretation must be made in light of your personal and family medical history. For instance, patients with Diabetes mellitus are at higher risk that non-diabetics with the same cholesterol level. Some general categories of risk are:
- Below 200
A cholesterol level below 200 mg/dL is desirable.
- 200 to 240
A cholesterol level of 200-240 mg/dL is "borderline high" and reflects moderate risk. Your doctor may decide to order a fasting lipid profile and tests such as C-reactive protein (CRP) to see if your high cholesterol is due to high LDL (bad) or high HDL (good). Depending on the results of the lipid profile, your doctor may order other tests.
- Above 240
A cholesterol level above 240 mg/dL is considered high risk. Your doctor may want to order a lipid profile and other tests to try to determine the cause of your elevated cholesterol.
NOTE: The Total Cholesterol is interpreted according to a test reference range (Normal range) and includes such specifics as age, gender and other factors.
A result within the "Normal" range for ANY test does NOT guarantee health, just as a test results outside the "Normal" range does NOT guarantee disease.