Lipoprotein(a): Understanding Your Genetic Cardiovascular Risk

This test measures how much Lp(a) is circulating in your blood. At its core an Lp(a) particle is an LDL particle: a cargo of cholesterol wrapped in exactly one molecule of apolipoprotein B. Attached to it, however, is a second protein, apolipoprotein(a). That protein closely resembles plasminogen, the molecule involved in dissolving blood clots. This dual role is what makes Lp(a) unfavourable: the particle can lodge in the artery wall the way LDL does, it carries inflammatory fats with it, and it also hampers the breakdown of clots.

The amount of Lp(a) in your blood is almost entirely set by the LPA gene. The decisive factor is the number of so-called KIV-2 repeats in that gene: the fewer repeats, the smaller the apo(a) protein and the more Lp(a) the liver releases. You inherit this from your parents, and it explains more than 90 percent of the difference between people. Your value is therefore already fixed before you have made a single lifestyle choice.

A warning about the units is in order. The laboratory reports Lp(a) in g/l, a unit of mass, as is the internationally common mg/dl: 0.30 g/l corresponds exactly to 30 mg/dl. Internationally, however, nmol/l is preferred, because that unit counts particles rather than weighing them. And because the apo(a) protein is much larger in one person than in another, the same number of particles does not weigh the same in everyone. There is therefore no fixed conversion factor between mg/dl and nmol/l: those units are not interchangeable. Compare results only within the same unit, and preferably within the same laboratory.

Lp(a) is an independent and causal risk factor for cardiovascular disease. Genetic research shows that people who naturally have a high Lp(a) more often suffer a heart attack or narrowing of the coronary arteries, even when their cholesterol, blood pressure and lifestyle are otherwise fine. That explains a pattern many people recognise: an apparently tidy lipid profile, and yet a strong family history of heart disease at a young age.

Risk rises gradually with the level. There is no sharp line below which you are safe and above which you are not, which is why European guidance uses orienting categories rather than a single hard cut-off. Roughly one in five people sits above the boundary that counts as raised, making Lp(a) one of the most common inherited risk factors for cardiovascular disease. At very high values the lifetime risk is comparable to that of people with inherited high cholesterol.

Lp(a) is also not only linked to furring arteries. It is independently associated with calcification and narrowing of the aortic valve, a connection absent from most patient pages but one that widens the clinical meaning of this value.

What matters most is what you do with the information. Statins do not lower Lp(a); they in fact raise it slightly. PCSK9 inhibitors lower it by roughly a quarter. Targeted medicines that suppress Lp(a) production far more strongly are in development, but no drug has yet been shown to prevent heart attacks by lowering Lp(a). Those outcome trials are still running. Promising is therefore not the same as proven.

A raised Lp(a) is consequently, today, above all a reason to tackle the risk factors you can influence more strictly: the number of atherogenic particles in your blood, read from ApoB and non-HDL cholesterol, your blood pressure, smoking and your blood sugar regulation. Your doctor decides with you what that means in practice.

Finally, the family. Because Lp(a) is passed on through a single gene, every first-degree relative of someone with a high value has roughly a 50 percent chance of carrying the same predisposition. Discuss with your doctor whether it is useful to raise this within your family.

Lp(a) comes with a recommendation that exists for almost no other blood value: have it measured at least once in your life. The 2022 European consensus statement advises this for every adult. The reason is simple: the value is genetically fixed, barely changes afterwards, and therefore does not need periodic checking. A single test yields a number that will serve you for the rest of your life.

There is extra reason to test when cardiovascular disease occurs at a young age in your family, when you already have cardiovascular disease yourself, when inherited high cholesterol is present, or when a first-degree relative has been found to have a raised Lp(a).

You do not need to fast: Lp(a) barely changes after a meal. Do avoid testing during or shortly after acute inflammation, an infection, surgery or a hospital admission, because Lp(a) behaves partly as an acute-phase protein and can then read temporarily higher. Severely reduced kidney function, nephrotic syndrome and an underactive thyroid can also lift the value; liver disease lowers it. In women, Lp(a) usually rises modestly after the menopause.

The categories below come from the European consensus and are intended as orientation, not as a cut-off.

The mg/dl and nmol/l columns sit side by side, but they are emphatically not interchangeable. The nmol/l figures are only a rough indication, because the conversion differs from person to person with the size of the apo(a) protein. Bear in mind, too, that the average Lp(a) value differs sharply by ancestry: people of African descent naturally have a considerably higher median value than people of European or South Asian descent. The same result can therefore mean something different in two people. Always have the value placed within your personal risk profile by a doctor.