A Hidden Blood Marker May Flag Heart Disease Risk, Yet Many Patients Never Ask About It

If your doctor tells you your cholesterol is in a healthy range, it’s natural to leave the appointment feeling reassured. But there is another blood marker that can raise the risk of heart disease and stroke, and it is not included in a standard cholesterol panel.

That marker is lipoprotein(a), usually shortened to Lp(a). Levels are largely inherited, so diet and exercise typically have little effect on them. As a result, a person can have high Lp(a) even with healthy habits and otherwise good cholesterol numbers.

Cardiologists say this test can reveal important information about cardiovascular risk, and they also explain what happens if the result is elevated.

What is Lp(a)?

Cholesterol moves through the bloodstream in particles called lipoproteins. According to Archna Bajaj, M.D., a lipid disorders specialist at Penn Medicine and associate professor of clinical medicine at the University of Pennsylvania, Lp(a) resembles an LDL particle, but with an extra protein attached.

Like LDL, Lp(a) can contribute to plaque buildup in the arteries, increasing the risk of heart attack and stroke. Higher levels are also associated with aortic stenosis, a condition in which the valve that allows blood to leave the heart becomes narrowed.

The challenge is that routine cholesterol results do not reveal what Lp(a) looks like, Dr. Bajaj says. She recently evaluated a woman in her late 40s who had no known medical problems and took no medications. Her LDL cholesterol was 110 mg/dL, but her father had suffered his first heart attack at age 50. Wanting to know whether her real risk was being missed, she asked Dr. Bajaj to check Lp(a).

The test came back above 300 nmol/L, roughly four times the upper limit of normal for that assay, which is less than 75 nmol/L. After initially hesitating to start medication, the patient agreed to take a statin once the risk tied to very high Lp(a) was explained and it became clearer that the result may help explain her father’s early heart disease, Dr. Bajaj says.

Who should get an Lp(a) test?

If you are an adult and have never had Lp(a) measured, it is worth asking about at your next visit, even if your cholesterol has always looked fine. Current guidance recommends that every adult have it checked at least once, and it is especially important if elevated Lp(a) runs in your family or if there is a history of early heart disease, meaning before age 55 in men or 65 in women.

The test is a simple blood draw that a primary care doctor can order, Dr. Bajaj says. Even though Lp(a) is mostly inherited, genetic testing is not required to measure it.

Fasting is not needed for the Lp(a) test, though you may want to confirm whether any other blood work ordered at the same time has different instructions. Before going to the lab, it is also wise to check insurance coverage and potential out-of-pocket costs.

What counts as a high Lp(a) level?

Before focusing on the number itself, pay attention to the units listed beside it. Lp(a) is reported either in nanomoles per liter, or nmol/L, or in milligrams per deciliter, or mg/dL. A result of 100 can therefore mean different things depending on the units used by the lab.

It is best to stick with the unit shown on the report rather than trying to convert it yourself, because there is no single dependable conversion formula, Dr. Bajaj explains.

And while elevated results can be concerning, those ranges only reflect risk related to Lp(a) itself. They do not, by themselves, predict whether someone will have a heart attack. Doctors also factor in age, other cholesterol values, blood pressure, medical and family history, smoking, and diabetes when estimating overall risk.

What can you do if your Lp(a) is high?

“I tell patients that elevated Lp(a) is largely inherited, so it is not a reflection of poor lifestyle choices or something they did wrong,” Dr. Bajaj says.

That said, healthy habits still matter. Good nutrition and regular exercise can improve blood pressure and blood sugar, which helps lower overall cardiovascular risk even when Lp(a) itself does not change much.

Medication may still be recommended. Cheng-Han Chen, M.D., a board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, California, says statins do not directly reduce Lp(a), but they do lower LDL cholesterol and help prevent heart attacks and strokes.

Decisions about medication should be based on a person’s full risk profile, says Daniel E. Soffer, M.D., an internist, clinical lipidologist, and associate professor of medicine at the University of Pennsylvania. Someone who already has heart disease may need a more aggressive LDL target than someone with fewer risk factors.

Researchers are studying treatments designed specifically for Lp(a), but none are approved for that use yet. Lipoprotein apheresis can remove Lp(a) and LDL from the blood, but Dr. Soffer says it is reserved for a small number of patients who meet specific criteria, including certain inherited cholesterol disorders and artery disease.

Will you need to see a cardiologist?

Not always. A primary care doctor can explain the result and outline next steps. If Lp(a) is very high, if early heart disease runs in your family, or if overall risk is unclear, a cardiologist or lipid specialist may be helpful.

In some situations, your doctor may discuss a coronary artery calcium scan, which checks for calcified plaque in the arteries that feed the heart. Yu-Ming Ni, M.D., a board-certified cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, California, says he uses the scan to help guide medication choices when risk remains uncertain.

If you have ever had preeclampsia or gestational diabetes, be sure to mention it, even if the pregnancy was years ago. “That history still matters when assessing your heart health,” says Tala K. Al-Talib, M.D., a cardiologist and medical director of cardiology at Johns Hopkins Greenspring Station.

Should your family get tested, too?

If your Lp(a) is elevated, let your siblings, parents, and adult children know, Dr. Bajaj recommends. Because high levels can run in families, your result may prompt relatives to get tested and uncover a risk factor they did not know they had.

For younger children, speak with their pediatrician first. The National Lipid Association recommends testing certain children, including those with a parent or sibling who has elevated Lp(a), rather than screening every child routinely.

The bottom line

If you have never had Lp(a) checked, it is worth asking at your next appointment: “Have I ever had my Lp(a) checked, and if it’s high, how would that change my prevention plan?”

Dr. Bajaj notes that pregnancy, menopause, and some health conditions, including kidney or thyroid disease, can affect the result. Tell your doctor what is going on with your health so they can decide when to test and whether it should be repeated. You may only need it once, but you should understand what the result means and what actions it points to for protecting your heart.

Learning that Lp(a) is high can be unsettling, especially if you have been trying to stay healthy. Even so, the information can help your doctor better manage your other risk factors.