Interpreting Your Cholesterol Test

A Cholesterol Test Can Also Help You To Understand Your Risk of Heart Disease

Pills on the results of blood testing, including testing for cholesterol
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As with any of the tests available out there to test your cholesterol, interpreting your cholesterol test can be sometimes confusing. Knowing what types of cholesterol are being tested and their normal levels will help you to interpret your cholesterol test and know your risk for heart disease.

Measuring blood fats is an important tool in determining your risk of cardiovascular disease. A lipid panel is a series of tests used to determine the amount of fat in your blood.

There are four major fat components that will be listed on your lipid panel:

  • Total cholesterol
  • Low-density lipoprotein (LDL)
  • High-density lipoprotein (HDL)
  • Triglycerides.

Each of these components is important in determining your risk for heart disease.

Total Cholesterol Levels

One of the readings you will see from your laboratory results is a number for "total cholesterol." This will tell you the total number of all of the fats you have in your blood. According to the National Cholesterol Education Program:

  • A desirable level is less than 200 mg/dL (5.17 mmol/L)
  • Levels between 200 mg/dL and 239 mg/dL (5.17–6.18 mmol/L) are considered borderline for high cholesterol.
  • Levels at or above 240 mg/dL (6.21 mmol/L ) are considered high total cholesterol levels. This may put you at an increased risk for heart disease.

It is important to note that you should not determine your cholesterol levels just by your total cholesterol level.

This needs to be further broken down into LDL, HDL, and triglycerides in order to give you some insight into the types of cholesterol that are in your blood.

High-Density Lipoproteins

High-density lipoproteins, or HDL, are considered to be the "good cholesterol", because HDL’s role in the body is to take cholesterol to the liver for degradation or processing, as opposed to allowing the cholesterol to hang around in the blood.

According to the National Cholesterol Education Program:

  • Any HDL level above more than 60 mg/dL (1.56 mmol/L) is considered high. A high HDL level is considered very healthy since it has a protective role in guarding against heart disease.
  • An acceptable HDL range is between 40- 60 mg/dL (1.04–1.56 mmol/L).
  • An undesirable level of HDL is any level below 40 mg/dL (1.04 mmol/L). In this case, low HDL levels may help to contribute to heart disease.

Triglyceride Levels

Elevated levels of triglycerides are also a risk factor for heart disease. According to the National Heart, Lung, and Blood Institute:

  • Triglyceride levels should be below 150 mg/dL (1.69 mmol/L).
  • Levels between 150 mg/dL (1.69 mmol/L ) and 199 mg/dL (2.25 mmol/L) are considered borderline high.
  • Levels between 200-499 mg/dL (2.26-5.63 mmol/L) are considered high.
  • Levels above 500 mg/dL (5.64 mmol/L) or considered extremely high.

Low-Density Lipoproteins

Low-density lipoproteins, also known as LDLs, are considered to be the "bad cholesterol". This type of lipoprotein circulates from the liver to other organs and tissues in the body, carrying cholesterol where it is needed. This type of cholesterol tends to linger and has been connected with various types of heart disease, including atherosclerosis, heart attack, stroke, and coronary heart disease.

The current guidelines for LDL levels are:

  • LDL levels less than 100 mg/dL ( 2.6 mmol/L) are considered optimal.
  • LDL levels between 100 – 129 mg/dL (2.6–3.34 mmol/L) are considered near or above optimal.
  • LDL levels between 130 – 159 mg/dL (3.36–4.13 mmol/L) are considered borderline high.
  • LDL levels between 160 – 189 mg/dL (4.14 - 4.90 mmol/L) are considered high.
  • LDL levels at or above 190 mg/dL (4.91 mmol/L) is considered very high.

LDL can be measured directly by using an instrument, or indirectly by using the Friedewald equation: 

                                             LDL = total cholesterol – HDL – (triglycerides/5)

Your ideal LDL level is determined by how many risk factors you have. So, although you might have an optimal LDL level, your health care provider may want it to be a little lower, based upon what types of conditions you have. For instance, a 60-year-old with diabetes and heart disease would want their LDL level much lower than a 30-year-old with no risk factors for heart disease. Although some risk factors can be modified, others cannot, such as age, gender, and family history of heart disease.

  • The highest risk patient group includes individuals who already have established cardiovascular disease (i.e. already had a heart attack or stroke), in addition to other conditions, such as metabolic syndrome, previous heart attack, high blood pressure, or smoking. This group of patients should have a goal of having an LDL less than 70 mg/dL (1.81 mmol/L).
  • Individuals who have coronary artery disease(CAD) or other vascular diseases (like diabetes, carotid artery disease, peripheral artery disease, or a previous abdominal aortic aneurysm) are considered at high risk. The LDL goal in these individuals is less than 100 mg/dL (2.6 mmol/L), although some health care providers may want this number below 70 mg/dL.
  • Individuals with two or more risk factors are considered at moderate risk of getting heart disease. Their LDL goal is less than 130 mg/dL (3.36 mmol/L).
  • Individuals with one or no risk factors are at low risk for getting heart disease. Their LDL goal is less than 160 mg/dL (4.14 mmol/L).

Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (PDF)

Heart Protection Study Collaborative Group. MRC/BHF heart protection study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomized placebo-controlled trial. Lancet 2002;360:7-22.

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