Lipoprotein(a): The Inherited Cholesterol Test Most People Never Get

Maybe a relative had a heart attack young, even with normal cholesterol. Maybe you saw "Lp(a)" on a lab form and wondered what it was. Lipoprotein(a) is a part of your cholesterol profile that most standard tests leave out. This guide explains what it is, who should be tested, and what a high result means.

What Lp(a) is

Lipoprotein(a), written Lp(a) and said "L-P-little-a", is a particle that carries cholesterol in the blood. It looks like an LDL particle (the "bad" cholesterol) with an extra protein attached, called apolipoprotein(a).

Lp(a) matters for three reasons [4]:

• It helps build plaque in arteries, like LDL.
• It may make clots more likely to form.
• It is linked to narrowing of the aortic valve (aortic stenosis).

Large genetic studies show that high Lp(a) causes heart disease, not just appears alongside it [4].

It is mostly inherited

Your Lp(a) level is set mainly by your genes. It stays fairly stable through adult life [1] [4]. That means a single test can tell you about lifelong risk. About 1 in 5 people have a raised level [3]. Levels tend to be higher on average in people of African and South Asian ancestry.

What your doctor looks at

Who should be tested

• The 2021 Canadian Cardiovascular Society (CCS) guideline was the first in North America to recommend measuring Lp(a) once in every adult, as part of the first lipid assessment [2].
• The National Lipid Association (NLA) in the US recommended in 2024 that every adult have Lp(a) measured at least once [3].
• The 2026 ACC/AHA dyslipidemia guideline also supports measuring Lp(a) at least once in adulthood [1].

Coverage for the test varies by province, state, and insurer. Ask before the test if cost is a concern.

What counts as high

Lp(a) can be reported in two units: nmol/L or mg/dL. The two units cannot be converted exactly, so look at which unit your lab used [1].

• NLA groups: below 75 nmol/L (30 mg/dL) is low risk, 75 to 125 nmol/L (30 to 50 mg/dL) is intermediate, and 125 nmol/L (50 mg/dL) or higher is high risk [3].
• The 2026 ACC/AHA guideline treats 125 nmol/L or 50 mg/dL or higher as a risk-enhancing factor [1].
• The CCS treats 50 mg/dL (about 100 nmol/L) or higher as a marker of higher risk that supports earlier and stronger treatment of other risk factors [2].

Risk rises steadily with higher levels. A very high level carries more weight than one just over the line [1].

How a high result changes care

There is no proven treatment aimed only at Lp(a) yet. So guidelines focus on lowering your total risk [1] [3]:

• Your clinician may treat LDL cholesterol earlier or more strongly, often with a statin.
• Blood pressure, diabetes, and smoking get extra attention.
• A high Lp(a) can tip a borderline statin decision toward treatment.
• Relatives may be offered testing, because high Lp(a) runs in families [3].

What about treatment for Lp(a) itself

• Diet, exercise, and weight loss have little effect on Lp(a).
• Statins lower LDL well but do not lower Lp(a). They are still used because they lower overall risk.
• Some other cholesterol drugs, such as PCSK9 inhibitors, lower Lp(a) modestly as well as LDL.
• In the US, lipoprotein apheresis, a filtering procedure like dialysis, is approved for a small group of very high-risk people with high Lp(a) and LDL [3].

New medicines can lower Lp(a) by a large amount. As of late 2026, large trials testing whether they prevent heart attacks and strokes were still under way, and final results were not yet available [1]. Ask your clinician about the latest status, because this field is changing fast.

Lp(a) and the aortic valve

High Lp(a) is also linked to calcific aortic stenosis, a narrowing of the main valve that lets blood leave the heart [4]. Aortic stenosis can cause shortness of breath, chest pain, and fainting with effort. It is often first found as a heart murmur. If your Lp(a) is high, your clinician may listen for a murmur at checkups.

Why so few people are tested

Lp(a) is not part of a standard cholesterol panel. For many years, guidelines only suggested it for people with a strong family history of early heart disease. Testing rates have been low, even after guidance changed [3]. If your clinician has not mentioned it, you can ask.

Reading your result

• Check the unit: nmol/L or mg/dL.
• Compare your number with the cutoffs your lab and clinician use.
• Remember that one high number does not mean you will have a heart attack. It means your other risk factors deserve more attention.

Questions to ask your clinician

• Has my Lp(a) ever been measured? If not, should it be?
• What is my level, and in which unit?
• How does my Lp(a) change my overall heart risk?
• Should my LDL goal be lower because of my Lp(a)?
• Should my parents, siblings, or children be tested?
• Would a coronary calcium scan help in my case?
• Am I a candidate for a clinical trial?

When to get care quickly

A high Lp(a) is a long-term risk, not an emergency. Call 911 for chest pain or pressure, shortness of breath, sudden weakness or numbness, trouble speaking, or fainting.

Bottom line

Lp(a) is an inherited particle that raises heart and valve risk in about 1 in 5 people. Canadian and US guidance now supports testing it once in adulthood. A high level is a reason to control LDL and other risk factors more firmly, while trials of Lp(a)-lowering drugs finish.

Primary AI can show you the guideline and study sources behind this topic in plain language, so you can bring better questions to your appointment.