Cholesterol, a building block of the outer layer of cells (cell membranes), is transported through the blood in the form of water-soluble carrier molecules known as lipoproteins. A low-density lipoprotein (LDL) is a class of lipoprotein particle that varies in size and content and carries fatty acid molecules in the blood. Low-density lipoprotein (LDL) cholesterol is a known risk factor for cardiovascular disease.

There are two main subclasses of LDL, called A and B. In subclass pattern A, the particles have a diameter larger than 25 nanometers (nm) and are less dense. Subclass B particles have a diameter less than 25 nm and a higher density. Subclass pattern B is an inherited disorder. This pattern includes elevated levels of triglycerides, and low levels of high-density lipoproteins (HDL). LDL subclass B is commonly seen in type II diabetes and is one component of the “metabolic syndrome,” defined by the Adult Treatment Panel (ATP III) to also include but are not limited to; high normal blood pressure, insulin resistance, and increased levels of inflammatory markers. This places an individual in a substantial risk-enhancing factor for coronary artery disease. 

Low-density lipoprotein (LDL) subclass testing has been proposed for use as part of an overall assessment of patient risk for cardiovascular disease (CVD). The LDL subclass test is a blood test that determines the LDL particle size pattern of an individual.  All LDL particles can invade the artery wall and begin the process of atherosclerosis (a build-up of fatty plaque on the artery wall). However, small, dense particles are thought to be more atherogenic compared to larger particles. It is thought that patients with elevated numbers of LDL particles have a higher cardiac risk factor.

Health care specialist are interested in measuring LDL subclasses as an indicator of CVD risk since there is a suggestion that unfavorable LDL subclass levels can be modified with behavioral changes including dietary changes, decreased body weight, and medications.

• In many individuals, an elevated blood cholesterol level indicates an increased risk of developing cardiovascular disease.
• Factors that affect blood cholesterol levels include age, sex, body weight, diet, alcohol and tobacco use, exercise, genetic factors, family history, medications, menopausal status, the use of hormone replacement therapy, and chronic disorders such as hypothyroidism, obstructive liver disease, pancreatic disease (including diabetes), and kidney disease.
• Therapy to reduce these risks includes diet, exercise and medication, and fat weight loss.
• LDL goal less than 70 is recommended for individuals with established coronary artery disease (CAD), noncardiac arthrosclerosis or coronary artery disease equivalent (i.e., diabetes mellitus).

Many studies have explored the role of subclass testing in the development of coronary artery disease or the metabolic syndrome. No studies have been identified which showed that the results of these tests were used to direct a patient’s treatment or management of a disease.

Will having LDL subclass testing improve my quality of life? 

Published data has yet to determine how subclass testing would guide treatment decisions.

How safe is this for me?

There are no problems associated with the test itself other than those associated with routine blood drawing.

No studies were identified in which identification of subclass patterns of LDL were used to direct patient management.

LDL subclass testing ranges from $140 to $175 and higher depending on what laboratory is used.

The cost may or may not be covered by your health benefits plan.

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