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You've probably had your cholesterol levels checked, or could very easily - it just takes a blood test. But what do these numbers mean, and what are they supposed to be?
Types of cholesterol measured
Well, naturally you'd think that a lab test for cholesterol would simply tell you how much cholesterol you have. And it does, but wait: There are several cholesterol measurements. These are:
- Total cholesterol.
- HDL cholesterol.
- LDL cholesterol.
Total cholesterol
HDL cholesterol is the "good" cholesterol carried on high-density lipoproteins.
Having more of it means you're more likely to have a lower risk of coronary heart disease (CHD).
LDL cholesterol is the "bad" cholesterol carried on low-density lipoproteins. You're better off with lower levels of LDL cholesterol, because it's associated with a higher risk of heart disease.
Note that total cholesterol doesn't equal HDL cholesterol plus LDL cholesterol. This is because there are still more types of cholesterol, which we won't talk about here.
Your cholesterol numbers
Cholesterol is measured as
milligrams of cholesterol per deciliter of blood, which is abbreviated like this: mg/dL.
Often, your total cholesterol is the only type tested. Or you may have both your total cholesterol and your HDL cholesterol tested at the same time.
If your total cholesterol is:
| 200 mg/dL or less |
Desirable cholesterol level |
| Between 200 and 239 mg/dL |
Borderline high cholesterol level |
| 240 mg/dL or more |
Too high |
If your HDL cholesterol is:
| Less than 40 mg/dL |
Too low |
| More than 40 mg/dL |
Beneficial especially if it's above 60 mg/dL |
People should have a lipid profile test (total cholesterol, HDL cholesterol and triglycerides) after an overnight fast. These tests allow the LDL cholesterol to be calculated.
Elevated triglycerides are common and a risk factor for CHD. Triglycerides may be elevated even if the total and HDL cholesterol are normal. So there is no way to know if a person has high triglycerides unless it is measured.
If you are 20 years old or older, have no heart disease and your LDL cholesterol is:
| Less than 100 mg/dL |
Desirable |
| 100 - 129 mg/dL |
Near optimal/above optimal |
| 130 - 159 mg/dL |
Borderline high |
| 160 - 189 mg/dL |
High |
| 190 mg/dL and above |
Very high |
If you already have CHD or diabetes, then your LDL cholesterol should be 100 mg/dL or less.
Your cholesterol ratio
Sometimes you'll be given your cholesterol results as a ratio of total cholesterol to HDL cholesterol. (This is the same thing as saying total cholesterol divided by HDL cholesterol.) According to the American Heart Association (AHA), the ratio should be below 5:1 with the optimal amount being 3.5:1 (3.5 to 1).
It's also possible to divide LDL cholesterol by HDL cholesterol to obtain a ratio. (This is the same thing as saying the ratio of LDL cholesterol to HDL cholesterol.) In this case, the ratio should be below 3.5.
However, the AHA recommends using absolute numbers for cholesterol (as discussed above) rather than ratios. The reason is that the absolute numbers give doctors a better idea of what type of treatment is needed by the patient, than do ratios.
Triglycerides
Your
triglycerides are another fatty substance in the blood that affects your risk for heart disease. Most fat in food, as well as in your body, is present in the form of triglycerides. High levels of triglycerides are a matter of concern and are linked to the risk of heart disease, just as with cholesterol.
If your triglycerides are tested, here is how you can interpret the numbers, according to the Third Report of the Expert Panel on the Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults:
| Less than 150 mg/dL |
Normal |
| 150 - 199 mg/dL |
Borderline |
| 200 - 499 mg/Dl |
High |
| More than 500 mg/Dl |
Very high |
Calculating LDL cholesterol
If your triglycerides are less than 400 mg/dL, your doctor can calculate your level of LDL cholesterol from your tested levels of total cholesterol and HDL cholesterol and triglycerides. The equation your doctor might use is:
LDL cholesterol = total cholesterol -- (HDL cholesterol + [triglycerides/5])
Remember, only your doctor should determine the best way to evaluate and interpret your cholesterol levels. Speak to your doctor if you have any questions about your cholesterol levels or the best way, given your unique needs, to reduce your risk for heart disease.
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Related Articles
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External Sources
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Third Report of the Expert Panel on the Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults, May 2003
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National Heart, Lung, and Blood Institute
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American Heart Association
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This article was reviewed and updated June 2007.
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