Apolipoprotein B (ApoB) is a structural protein found on the surface of lipoproteins, which transport fats and cholesterol throughout the bloodstream. A single ApoB molecule is found on every potentially harmful, plaque-forming particle, including low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and lipoprotein(a). Measuring ApoB offers a direct method for assessing cardiovascular risk by counting the number of these circulating particles. This measurement is an important tool for health providers seeking a clearer picture of an individual’s risk of heart disease.
Why Apolipoprotein B is Measured
The standard measurement for heart disease risk was low-density lipoprotein cholesterol (LDL-C), which measures the mass of cholesterol inside the lipoprotein particles. ApoB, by contrast, measures the actual number of these particles circulating in the blood. Since atherosclerosis is driven by the number of particles that penetrate the artery wall, ApoB is considered a more accurate predictor of risk than LDL-C.
Each ApoB-containing particle can become trapped in the artery wall, regardless of its cholesterol content. This distinction is significant for individuals with metabolic syndrome, diabetes, or high triglycerides. In these cases, LDL-C can appear normal while the ApoB count is high, a situation known as discordance. When LDL-C and ApoB levels disagree, ApoB is a stronger indicator of future coronary events.
Steps to Requesting the Test
The process of getting an ApoB test begins with a conversation with your healthcare provider, typically a primary care physician or a specialist like a cardiologist. Discuss your personal and family history of cardiovascular disease and any existing risk factors you may have. If your provider agrees the test is necessary for a comprehensive risk assessment, they will order it from a commercial laboratory.
The ApoB test is a simple blood draw performed at a lab or clinic, similar to a standard cholesterol panel. While ApoB can be measured in a non-fasting state, it is often ordered alongside other lipid tests that require fasting. You may be asked to fast for 9 to 12 hours before the draw, consuming no food or drink other than water during that period.
Insurance coverage for the ApoB test (CPT code 82172) can vary. While many major health organizations now recommend the test, it may not be standardly covered by all insurance plans depending on your risk factors. Check with your insurance provider beforehand to understand any out-of-pocket costs. Results are usually available within a few days after the blood sample is collected.
Understanding Your ApoB Test Results
ApoB levels are measured in milligrams per deciliter (mg/dL) and provide a straightforward numerical representation of your atherogenic particle count. Elevated ApoB levels indicate an increased number of harmful particles, which raises the risk of plaque buildup and subsequent cardiovascular events. The goal of any therapeutic intervention is to lower this particle count to reduce your overall risk.
For a person at low or moderate risk of heart disease, an ApoB level below 90 mg/dL is considered optimal. For individuals at high risk, such as those with diabetes, metabolic syndrome, or multiple risk factors, the target is often more aggressive, aiming for levels below 70 mg/dL. For people who have already experienced a cardiovascular event, the goal may be even lower, sometimes below 60 mg/dL. Your healthcare provider will interpret your specific result within the context of your complete health profile to determine your personal target range.