Most people who have had a cholesterol test know their LDL, the so-called bad cholesterol. Very few know their lipoprotein(a), usually written Lp(a) and pronounced "L-P-little-a." That is a gap worth closing, because Lp(a) is one of the most common inherited risk factors for heart disease, and the only way to find out whether you have high levels is to ask for a specific blood test.
What it is
Lp(a) is a particle that looks a lot like LDL cholesterol with an extra protein, apolipoprotein(a), attached. That extra protein appears to make the particle more likely to promote plaque buildup, inflammation and possibly clotting. High levels are linked to heart attacks, strokes and calcific aortic valve stenosis, a stiffening of the heart's main outflow valve.
The 2022 European Atherosclerosis Society consensus statement1 concluded that the evidence from large epidemiologic and genetic studies strongly supports a causal and continuous relationship between Lp(a) and cardiovascular outcomes. The higher the level, the higher the risk. That relationship holds even when LDL cholesterol is low.
Why one test is usually enough
Unlike LDL, which moves with diet, weight and medication, Lp(a) is largely set by your genes. According to the National Heart, Lung, and Blood Institute3, levels are mostly inherited and stay fairly stable over a lifetime. Diet and exercise have little effect on it.
That is why the European panel recommends measuring Lp(a) at least once in every adult. A single result tells you which category you are likely to be in for life. Because it is inherited, a high result in one person is also a reason for parents, siblings and children to be tested.
The higher the level, the higher the risk. That relationship holds even when LDL cholesterol is low.
Reading the result
Lp(a) can be reported in two different units, milligrams per deciliter or nanomoles per liter, and the numbers are not directly interchangeable. The 2018 American Heart Association and American College of Cardiology cholesterol guideline2 lists an Lp(a) of 50 milligrams per deciliter or higher, or 125 nanomoles per liter or higher, as a risk-enhancing factor. Roughly one in five people worldwide have levels in that range, and the share is higher in people of African ancestry.
A risk-enhancing factor is not a diagnosis. It is information that shifts the overall picture. For someone whose risk calculator puts them in a gray zone, a high Lp(a) can tip the decision toward starting a statin or treating blood pressure more aggressively.
What you can do about it
There is an awkward truth here. As of this writing, no therapy is approved in the United States specifically to lower Lp(a) for the purpose of reducing heart events, though drugs designed to do exactly that are in late-stage outcome trials. That research is moving quickly, and it is worth asking your clinician where it stands.
In the meantime, a high Lp(a) changes the plan in practical ways. The European consensus recommends early, intensive management of every other risk factor, scaled to a person's overall risk. That usually means getting LDL cholesterol lower than it otherwise might be, controlling blood pressure carefully, not smoking, and staying on top of blood sugar and weight. Some cholesterol drugs, including PCSK9 inhibitors, modestly lower Lp(a) as a side benefit. For people with very high levels and progressive disease despite treatment, a filtering procedure called lipoprotein apheresis is an option at specialized centers.
The logic is simple. You cannot easily change the inherited risk, so you shrink every risk you can change.
A high result can also change how closely you are followed. Some clinicians use it as a reason to consider a coronary artery calcium scan, which can show whether plaque has already formed, or to check for early signs of aortic valve narrowing during routine exams. None of that requires panic. It requires a plan that accounts for the number.
Who should prioritize testing
Anyone can ask for the test, and the European recommendation is universal. It is especially worth doing if you have a personal or family history of heart attack or stroke at a young age, meaning before 55 in men or 65 in women, if you have familial hypercholesterolemia, or if you have heart disease that seems out of proportion to your other risk factors. It is also useful when deciding about treatment if your risk is borderline.
The test is a standard blood draw, and because Lp(a) is mostly set by genetics, most adults need it only once. It is not part of a basic lipid panel, so you usually have to request it by name. Results come back in either milligrams per deciliter or nanomoles per liter, and the two units do not convert cleanly, so ask which one your lab used before comparing your number to anything you read online. A high result is also worth passing along to siblings and grown children, since it runs in families.
