Cholesterol Tests From A to Z

By Sondra Forsyth

According to the Centers for Disease Control and Prevention (CDC), heart disease is the leading cause of death in the United States—more than even all types of cancer combined. One of the simplest indicators of a person’s heart health is their cholesterol levels. But what exactly is cholesterol, and what kind of tests are available? Dr. Robert Segal, a board-certified cardiologist and founder of Manhattan Cardiology, has answers to those questions and more.

First and most importantly, what exactly is cholesterol?

“Cholesterol is a natural, waxy substance made by the liver that’s found in most tissues of the body. It has a lot of important uses from digestion to hormone production,” says Segal.

The liver produces enough cholesterol for all of the body’s functional needs, but cholesterol can also be found in many foods. In effect, this dietary cholesterol can lead to having too much cholesterol overall in the body—and in particular in the bloodstream—where it starts to stick together and build up.

“Because of cholesterol’s waxiness, it can stick to the inner walls of arteries. Once that starts, more and more cholesterol tends to build up, narrowing and hardening the arteries. This increases blood pressure, decreases the supply of oxygen to the heart, and can directly cause a heart attack,” says Segal.

There are a few different types of cholesterol that are important to know about.

Low-density lipoprotein (LDL). This is often referred to as “bad” cholesterol or “L” for “lousy”, although the body does need a small amount of LDL cholesterol for normal functioning. Lower LDL levels are associated with lower risk of heart disease and stroke.

High-density lipoprotein (HDL). This is often referred to as “good” cholesterol. HDL cholesterol can collect extra LDL cholesterol and return it to the liver to be broken down and removed from the body. Higher HDL levels are associated with lower risk of heart disease and stroke.

Triglycerides. This is a type of fatty compound the body uses to store extra energy. Triglycerides can be broken down later to release energy, but if the need never arises, the fat continues to build up. Lower levels of triglycerides are generally healthier.

“Often times when someone’s cholesterol levels are too high, there aren’t any noticeable symptoms until they have a heart attack or a stroke. But if someone knows they have high cholesterol, there’s a lot that can be done to lower their risk of those dramatic outcomes. That’s why it’s so important for people to regularly have their cholesterol levels tested. This is generally a simple procedure that can be performed during an annual physical,” says Segal.

There are several types of cholesterol tests available. Some are more generalized, while others have more specific uses.

• Lipid Panel. This very common test can be performed in a doctor’s office and yields results in a couple of days. Blood is drawn and sent to a laboratory for analysis. This type of test typically directly measures total cholesterol, HDL, and triglycerides, and then uses this information to calculate LDL levels.

• HDL-C test. This test is usually ordered as needed as a follow up test to a standard lipid panel. It can show whether HDL levels have gone either up or down since a previous screening.

• LDL-C test. Where a standard lipid panel uses a formula to calculate LDL levels, this test directly measures LDL cholesterol. For people with very high triglyceride levels, this may provide a more accurate assessment of LDL levels.

• Lipoprotein (a) = LpA  The amount of lipoprotein in your blood is determined by a lipoprotein test. You may be at an increased risk for heart disease and stroke if you have a high level of lipoprotein (a). 

• CAC test. A coronary artery calcium score uses a CT scan instead of a blood draw. The scan measures the amount of calcium in the arteries around the heart to determine how much plaque is built up. This type of test can help doctors decide if someone would benefit from taking statins (a type of medication) to lower their cholesterol. The higher the calcium score, the higher risk of heart disease.

“Cholesterol tests are an efficient and effective way to find out if someone’s cholesterol levels are too high. But that information is only useful if some sort of action is taken,” says Segal.

While statins and other medications are one available option, most of the time the most significant long-term benefits can be gained from making lifestyle changes.

A diet low in trans fat and saturated fats, refined sugars, and red meats can help lower cholesterol. These foods can be replaced with fish, fresh vegetables, nuts, legumes, seeds, and whole grains. Regular moderate exercise, healthy sleep habits, managing stress, maintaining a healthy weight, and quitting tobacco products are also all associated with improved heart health.

“The best part is that these options don’t require special equipment or a prescription. They’re simple concepts that most people understand intuitively. Sometimes it’s just about getting back to basics,” said Segal.

Manhattan Cardiology is the premier facility for preventive cardiology treatment in New York. Our cardiologists practice under the guiding principle that early detection is the best form of prevention.  www.manhattancardiology.com