Apolipoprotein A1 Test: What It Means

What Is Apolipoprotein A1?

Apolipoprotein A1 is a protein found in high-density lipoprotein, also known as HDL or good cholesterol. It helps start the process that removes harmful cholesterol from your bloodstream.

Apolipoprotein A1 supports heart health by helping HDL transport cholesterol to the liver for removal. This is why the biomarker is often used to understand your risk for cardiovascular disease. Although doctors commonly check HDL and LDL levels, apolipoprotein A1 can give additional insight, especially when standard cholesterol results are unclear.

When Is Apolipoprotein A1 Testing Recommended?

Doctors may recommend this test when they want a more detailed understanding of your heart disease risk.

Common reasons include:

• Family history of early heart disease
• Personal history of heart problems
• Low or unusual HDL cholesterol levels
• Monitoring certain cardiovascular risk factors
• When standard lipid results do not match your symptoms or risk profile

How Is Apolipoprotein A1 Testing Conducted?

Apolipoprotein A1 is measured through a blood test. A sample is taken from a vein in your arm and sent to a laboratory for analysis.

This biomarker can be included in advanced cholesterol assessments or specialized lipid evaluations.

Most people do not need special preparation for the test. Your doctor may ask about smoking or supplements because both can affect your results. You may also need to stop certain substances before testing, but only if your doctor advises it.

What Are the Normal Apolipoprotein A1 Levels?

Normal values are usually:

• Men: 110 to 180 mg/dL
• Women: 110 to 205 mg/dL

Note: The units of measurement and the normal ranges can differ depending on the laboratory and the specific methods used.

What Do Abnormal Levels Mean?

Apolipoprotein A1 High Levels

High levels of apolipoprotein A1 are uncommon but can occur. They usually indicate that the body is producing more of the protein linked to HDL cholesterol.

Possible causes include:

• Familial hyperalphalipoproteinemia: A rare inherited condition that leads to very high HDL levels.
• Cholesteryl ester transfer protein deficiency: A genetic disorder that affects how cholesterol moves through the body.
• Weight loss: Losing weight can temporarily raise HDL and apolipoprotein A1.
• Hormone-containing substances: Some forms of hormonal intake may raise apolipoprotein A1.

• Maintain a balanced diet to support healthy cholesterol levels.
• Keep active to stabilize HDL levels.
• Discuss genetic testing with your doctor if high levels run in your family.
• Review any hormonal products or supplements with your doctor.

Apolipoprotein A1 Low Levels

Low apolipoprotein A1 levels often signal low HDL cholesterol. This may increase your risk for cardiovascular disease.

Possible causes include:

• Familial hypoalphalipoproteinemia: An inherited condition that causes low HDL and low apolipoprotein A1.
• Tangier disease: A rare genetic disorder that severely reduces HDL levels.
• Liver disorders: The liver helps produce apolipoprotein A1, so certain conditions can lower it.
• Poorly controlled diabetes: High blood sugar affects lipid metabolism.
• Nephrotic or kidney disorders: Some kidney problems cause loss of proteins, including apolipoprotein A1.
• Coronary artery disease: Low HDL markers may be linked to plaque buildup in heart arteries.
• Cholestasis: Problems with bile flow can alter lipid levels.
• Smoking: Smoking lowers HDL and apolipoprotein A1.
• Androgen-containing substances or diuretics: Certain products may reduce HDL-related proteins.

• Quit smoking to improve HDL levels.
• Maintain stable blood sugar if you have diabetes.
• Focus on regular exercise to boost HDL naturally.
• Eat foods rich in heart-healthy fats.
• Discuss kidney or liver symptoms with your doctor.
• Review any supplements or hormones with your doctor.

Which Specialist Should You Consult?

A cardiologist is the primary specialist for low or high apolipoprotein A1 levels.

Depending on the underlying cause, you may also be referred to:

• An endocrinologist for metabolic or diabetes-related issues
• A nephrologist for kidney-related conditions
• A hepatologist for liver disorders