Why get a cholesterol test? For decades, doctors have known that people with high total cholesterol levels are at higher risk for heart disease. More recently, they've found the different forms of cholesterol ("good" and "bad") also affect risk.
Cholesterol Tests: the Good, Bad, the Fatty
Cholesterol is a form of fat that's not all bad -- a certain amount is essential for life. Cholesterol helps provide stability to the outer membranes of our bodies' cells.
But cholesterol can have harmful effects. LDL -- or "bad" -- cholesterol can deposit in blood vessel walls. Over years, LDL cholesterol and other substances clog arteries in the process called atherosclerosis. Arteries in the heart narrowed by atherosclerosis can then develop sudden blood clots, causing heart attacks.
Having high total cholesterol, high bad cholesterol, or low good cholesterol could place you at higher than average risk for heart disease. Knowing about high cholesterol is the first step toward lowering it, which reduces your risk. That's the reason to get a cholesterol test.
An Overview of Cholesterol Tests
There are multiple forms of cholesterol circulating in the blood. The various forms of cholesterol and other fats in the blood are together called lipids. Doctors measure and diagnose high cholesterol with a simple blood test, often called a lipid profile. It's often done after fasting for nine to 12 hours to eliminate the contribution of any food you recently ate.
Tests for cholesterol provide results for four different types of lipids.
- Total cholesterol
- LDL (low-density lipoprotein), the "bad cholesterol"
- HDL (high-density lipoprotein), the "good cholesterol"
- Triglycerides, another form of fat in the blood
Some lipid panels provide more detailed information, with information on the presence and sizes of various fat particles in the blood. Research is ongoing into the possible contribution to heart disease of these factors. Currently, there is no consensus on when more advanced testing of fat particle size is necessary.
Understanding Your Cholesterol Test Results
So you've gone hungry overnight, endured a small bloodletting, and dutifully returned to receive your lipid panel test results. Now, what do the numbers in your lipid panel mean?
For total cholesterol:
- 200 milligrams per deciliter (mg/dL) or less is considered normal.
- 201 to 240 mg/dL is borderline.
- Greater than 240 mg/dL is considered high.
For HDL ("good cholesterol"), more is better:
- HDL 60 mg/dL or higher is good -- it protects against heart disease.
- HDL between 40 and 59 mg/dL are acceptable.
- Less than 40 mg/dL HDL is low, increasing the risk of heart disease.
For LDL ("bad cholesterol"), lower is better:
- An LDL of less than 100 mg/dL is optimal.
- An LDL of 100 to 129 mg/dL is near-optimal.
- LDL between 130 and 159 mg/dL is borderline high.
- LDL cholesterol between 160 and 189 mg/dL is high.
- An LDL of 190 mg/dL or more is considered very high.
Your personal LDL goal depends on your risk for heart disease:
- For people at high risk of heart disease, or with known heart disease, LDL less than 100 mg/dL is advised. Your cardiologist might recommend an even lower LDL (less than 70 mg/dL) for patients at very high risk of heart disease.
- For people at moderate-to-high risk, LDL less than 130 mg/dL is the goal.
- People at low-to-moderate risk have a goal LDL of less than 160 mg/dL.
Your doctor can help you determine your overall heart disease risk profile, and your personal LDL goal.
High triglycerides (150 mg/dL or greater) also increase the risk for heart disease somewhat.
What to Do About Abnormal Cholesterol Test Results
If your lipid panel test results aren't what you hoped for, take action.
Everyone with an abnormal lipid panel blood test should make lifestyle changes to reduce heart disease risk, including:
- Diet. A diet low in saturated fat (7% of total calories or less) and cholesterol (200 mg or less daily) can lower LDL cholesterol. Adding fiber and plant sterols (found in special margarines and other foods) helps, as well. A cholesterol-lowering diet can reduce bad cholesterol by up to 30%.
- Exercise. Regular aerobic exercise can both lower bad cholesterol (LDL) and increase good cholesterol (HDL).
- Medication. If diet and exercise don't lower cholesterol levels to goal, drug treatment may be needed.
A variety of medications or combination treatments can lower cholesterol including:
- Statins, the most effective and commonly used cholesterol drugs
- Bile acid sequestrants
Because so many factors contribute to heart disease, cholesterol isn't destiny. People with normal cholesterol can have heart disease; people with high cholesterol can have healthy hearts. Overall, though, more people who have abnormal cholesterol levels will develop heart disease, compared to people with normal cholesterol tests.
Experts recommend follow-up cholesterol testing every five years for most people. People with abnormal lipid panels, or who have other risk factors, need more frequent cholesterol exams. By working to improve the results on your next cholesterol test -- or to keep your numbers looking good -- you'll reduce your risk for heart disease.