Top tips to understand cholesterol measurement

Monitoring your cholesterol levels is a good move if you want to ensure you’re not at risk of heart disease. These tips will help you choose the best method for you.

High levels of the "bad" kinds of cholesterol and other blood fats or lipids raise your risk for heart attack, stroke and other major maladies.

Specifically, a type of blood fat called low-density lipoprotein (LDL) and fats in the blood called triglycerides promote the build-up of artery-narrowing plaque and up your heart disease risk.

Not all types of cholesterol are bad, however. High-density lipoprotein (HDL), or "good," cholesterol actually protects against heart disease. Keeping bad cholesterol levels low and good cholesterol levels high is essential for good health.

A cholesterol blood test measures the following various components of fats in your blood:

• Total cholesterol. This is the sum of HDL plus LDL, measured in millimoles per litre (mmol/L) of blood. Experts recommend that your level of cholesterol be evaluated, and Health Canada guidelines suggest that your total cholesterol be kept under 5.2 mmol/L, and recommend that the HDL level within this number be kept at 25 percent or more of the total.
• LDL ("bad") cholesterol. LDL levels should be kept below 3.5 mmol/L, if possible. Levels ranging from 3.5 to 3.9 mmol/L are borderline-high; and over 4.0, high.
• HDL ("good") cholesterol. HDL levels of 0.9 mmol/L or above are considered to be protective against heart disease. Conversely, lower levels could put you at risk.
• Triglycerides. Levels of 2.0 mmol/L or less are considered normal; 2.0 to 3.0 are considered borderline-high; more than 3.0 mmol/L is considered high.

Blood is drawn, usually from your arm, and sent to a lab where lipid levels are measured. Let your doctor know of any drugs or supplements you may be taking, as some may interfere with test results. Eat your normal diet for one week prior to the test; your doctor will instruct you on fasting 12 to 14 hours before the test. Don't drink alcohol for a day before the test.

Most experts recommend regular cholesterol screening every five years for men over age 40 and women over age 50 if healthy and not at high risk for heart disease.

Initial tests should measure total cholesterol as well as levels of HDL, LDL and triglycerides.

Take a test more frequently if:

• You are obese and/or physically inactive.
• You have diabetes.
• You have a family history of heart disease.
• You already have high cholesterol.
• All of the above.
• You should have your cholesterol checked by a doctor every three to six months.

Various testing kits are available for monitoring your cholesterol levels at home. For these tests, do the following:

• Prick your finger with a lancet device to draw a drop or two of blood.
• Place on a special test strip.
• After a few minutes, the test strip changes colour.
• Matching the colour change to a chart gives you your total cholesterol number.

Getting total cholesterol, rather than levels of HDL, LDL and triglycerides - all of which are important for assessing your overall heart disease risk - is a key drawback to these home tests.

If you already have high cholesterol or are at high risk for heart disease, it is important that you get regular cholesterol tests at your doctor’s office, including an assessment of levels of the different types of blood fats.

These tips will help you to understand cholesterol and monitor it for best health.