Cholesterol testing screens for risk of atherosclerosis which can lead to coronary heart disease, heart attack, and stroke. Atherosclerosis is a disease in which excess cholesterol in the bloodstream forms a build-up of fatty plaque on the artery walls. As this build-up increases, it narrows the arteries and restricts blood flow to the heart and brain.
Restricted blood flow to the heart can cause chest pain or angina. When blood flow to the heart becomes severely restricted or blocked completely, it can result in a heart attack.
The carotid arteries of the neck supply blood to the brain. If a carotid artery becomes blocked it can result in a stroke. A general explanation of cholesterol follows below.
What is cholesterol?
Cholesterol is a fat-like substance that your body needs to function properly. Your body uses it to make essential substances such as cell walls and hormones.
What is HDL or “good” cholesterol?
HDL means High Density Lipoprotein. HDL carries excess cholesterol away from the arteries to the liver where it is passed from the body. High levels of HDL can protect from cholesterol build-up formed by LDL (”bad” cholesterol) and reduce your risk of atherosclerosis.
What is LDL or “bad” cholesterol?
LDL stands for Low Density Lipoprotein. LDL is considered to be “bad” because it is the primary cause of the build-up on the artery walls. LDL is not measured directly but is calculated using the following formula:
Total Cholesterol - HDL - (triglycerides / 5)
What are triglycerides?
Triglycerides consist of fatty acids and glycerol. They are the most common type of fat like cholesterol, they circulate in your blood. Triglyceride levels increase significantly after you eat, then gradually, as your body processes the fat, the triglyceride levels decrease again.
High levels of triglycerides, in addition to high levels of LDL, may further increase risk for coronary heart disease.
What is Total Cholesterol?
Total Cholesterol (TC) is a combination of HDL (”good” cholesterol), LDL (”bad” cholesterol), and triglycerides. That is why you always hear that your Total Cholesterol level should be low.
Your body produces all of the cholesterol it needs. The cholesterol in your diet only serves to raise your blood cholesterol level, possibly increasing your risk of atherosclerosis. If your total cholesterol is low, then generally speaking, other parameters are kept in check.
While Total Cholesterol serves as a general indicator of the level of cholesterol in your blood, looking at Total Cholesterol alone can be misleading. The amount of HDL in your blood and the ratio of total cholesterol to HDL; good cholesterol. (TC/HDL) are also significant indicators. The reason is because of the positive effect HDL cholesterol has in removing LDL cholesterol from your blood and arteries.
What is the TC/HDL ratio?
This is the ratio of your level of HDL (”good” cholesterol) to your level of Total Cholesterol. To calculate your ratio, simply divide your level of Total Cholesterol by your level of HDL.
This ratio is considered to be a significant factor in accessing your risk of atherosclerosis.
Is fasting required before taking the test?
It depends on the test. Fasting is not required before testing for Total Cholesterol and HDL; fasting is required before testing for triglycerides (also recommended for glucose).
• It is not necessary to fast before evaluating Total Cholesterol and HDL.
• While triglycerides are included in Total Cholesterol, they are not present in large enough quantities to affect the evaluation of Total Cholesterol and HDL significantly. Recent food intake affects Total Cholesterol test results by less than 1.5%.
• Triglycerides, can increase markedly after eating, hence affecting the calculation outcome of LDL. Because of this factor, you should fast before testing triglycerides in order to achieve accurate results.
• Do not ingest anything except water, black coffee, and prescribed medications for 12 hours prior to testing.
What are the guidelines for evaluating my test results?
The following table indicates desirable results for all aspects of a complete cholesterol test as described above.
TC or Total Cholesterol Below 200mg/dl Less is better No Fasting Required
HDL (good cholesterol) Above 40 More is better No Fasting Required
TC/HDL ratio Below 3.5 Less is better No Fasting Required
LDL (bad cholesterol) Below 100mg/dl Less is better Yes Fasting Required
Triglycerides Below 130mg/dl Less is better Yes Fasting Required
Notes:
1. The figures above have been prepared by the National Heart, Lung and Blood Institute.
2. Measurements are in milligrams per deciliter (mg/dl).
For additional information on cholesterol, atherosclerosis, coronary heart disease, heart attack and stroke, please visit the following websites for risk factors, prevention and treatment:
• American Heart Association
• Coronary Heart Disease
• High Blood Cholesterol
• Check Your Cholesterol and Heart Disease I.Q.
Resources:
For more information about lowering cholesterol and lowering your risk for heart disease, write to the NHLBI Health Information Center, P.O. Box 30105, Bethesda, MD, 20824-0105 or call 301-592-8573, or visit the Web sites listed below:
• “Live Healthier, Live Longer”–information on cholesterol lowering (www.nhlbi.nih.gov/chd)
• “Aim for a Healthy Weight” (www.nhlbi.nih.gov)
• “Your Guide to Lowering High Blood Pressure” (www.nhlbi.nih.gov/hbp)
Other sources to review:
• www.nutrition.gov
• www.fitness.gov
• www.cdc.gov/tobacco
• “Healthfinder”–a free gateway to reliable consumer health and human services information developed by the U.S. Department of Health and Human Services (www.healthfinder.gov)
• www.yourtotalhealth.ivillage.com
• “MedlinePlus”–up-to-date, quality health care information from the National Library of Medicine at the National Institutes of Health (www.medlineplus.gov)
• American Stroke Association
Ask For More Information Related To Esoteric Tests That Give More Information Regarding Regulation Of Lipids And Heart Disease.
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