Apolipoprotein A1
Apolipoprotein A1 (ApoA1) is the main structural protein of HDL, your "good" cholesterol particles. Measuring it reflects how much functional HDL you have available to help remove excess cholesterol from your tissues and arteries.
ApoA1 supports reverse cholesterol transport, the process of shuttling cholesterol back to the liver for disposal, so higher levels are generally associated with cardiovascular protection. It can offer a more direct read on your protective HDL machinery than HDL cholesterol alone and is often paired with ApoB to assess the balance between harmful and protective particles.
A high ApoA1 generally reflects abundant protective HDL particles and is usually viewed favorably. Very high levels are not typically a concern on their own, though HDL function, not just quantity, ultimately matters, so an unusually high value is still interpreted in context.
A low ApoA1 suggests fewer protective HDL particles and can be associated with higher cardiovascular risk, and is sometimes seen with insulin resistance, poorly controlled diabetes, or certain genetic conditions.
Higher ApoA1 is generally better, with typical reference ranges often starting around 120 mg/dL in men and 140 mg/dL in women, but ranges vary by lab and should be interpreted with a clinician alongside ApoB and your overall risk.
Sources
- Cleveland Clinic: Apolipoprotein A (Apolipoprotein A1) Test
- MedlinePlus: Apolipoprotein A1 Blood Test
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.