📚 Part of our Heart Health Guide — an evidence-based guide.
There is a cardiovascular risk factor that affects roughly one in five people, is set almost entirely by genetics, is not measured in a standard cholesterol panel, and that most people have never heard of. It is called lipoprotein(a), written Lp(a) and said “L-P-little-a”.
What it is
Lp(a) is an LDL particle with an additional protein — apolipoprotein(a) — wrapped around it. That extra protein changes its behaviour in two ways that compound each other.
It is atherogenic, depositing in artery walls like LDL and carrying oxidised phospholipids that provoke inflammation. And because apo(a) structurally resembles plasminogen, a protein involved in dissolving clots, it appears to interfere with clot breakdown. So it plausibly both builds the plaque and impedes the clearing of a clot when that plaque ruptures.
It is also independently associated with calcific aortic valve stenosis — a link not shared by ordinary LDL.
Why it deserves a test
Your level is roughly 80–90% genetically determined and stable across life. Diet, exercise and weight barely move it. That is the whole reason it needs to be measured: nothing about your lifestyle reveals it.
Because it is stable, a single measurement is generally enough for a lifetime — unusual for a blood test, and a genuinely good deal.
Elevated Lp(a) is common: about 20% of people worldwide, with higher average levels in people of African ancestry and lower in East Asian populations. It is a plausible explanation for premature heart attacks in people whose standard panel looks fine, and for strong family histories that LDL alone does not account for.
Reading the result
Two units are in use, which causes confusion. Roughly: under 30 mg/dL (about 75 nmol/L) is low risk; 30–50 mg/dL is intermediate; above 50 mg/dL (about 125 nmol/L) is elevated, with risk continuing to rise at higher values.
Molar units (nmol/L) are preferred, because mass units are affected by variation in particle size between individuals.
An important framing point: a high result is a risk marker, not a diagnosis, and most people with elevated Lp(a) never have a heart attack. It shifts your baseline risk upward; it does not determine the outcome.
The uncomfortable part: there is no approved treatment
This is the honest limitation, and it is the reason some clinicians still do not test.
No approved drug specifically lowers Lp(a) to reduce cardiovascular events. Statins do not lower it, and may raise it slightly. Niacin lowers it but has failed to improve outcomes in trials and is not recommended. PCSK9 inhibitors reduce it by roughly 20–25%, but as a secondary effect. Apheresis exists for extreme cases and is rarely used.
Several targeted therapies — RNA-based drugs that lower Lp(a) dramatically — are in late-stage outcome trials. They have not yet demonstrated that lowering Lp(a) reduces heart attacks. That is the question those trials exist to answer, and it is not yet answered.
So why test at all
Because knowing changes how aggressively everything else is managed.
An elevated Lp(a) is a reason to treat LDL more aggressively, since you cannot lower Lp(a) but you can lower the total atherogenic burden (how low to go). It is a reason to control blood pressure tightly, not smoke, and address insulin resistance. It supports considering a coronary calcium score to see whether disease is actually present. And it is information for your family — children of someone with elevated Lp(a) have roughly a 50% chance of inheriting it.
When to see a doctor
Ask to be tested if you have a personal or family history of early cardiovascular disease — before 55 in men, 65 in women — a family history of elevated Lp(a) or familial hypercholesterolemia, aortic stenosis, or recurrent events despite well-controlled LDL. Several cardiology societies now support testing every adult at least once.
Seek emergency care for chest pressure, pain radiating to the arm or jaw, sudden shortness of breath, or new fainting on exertion — regardless of any lab value.
The honest bottom line
Lp(a) is a common, inherited, largely unmodifiable cardiovascular risk factor that a standard panel misses. One test covers a lifetime. There is no approved therapy that lowers it and no proof yet that lowering it helps — but knowing your number sharpens every other decision about your cardiovascular risk, and tells your children something they should know.
Since Lp(a) cannot be lowered, LDL treatment carries more weight — and most reported statin side effects are not caused by the drug.
Frequently asked questions
What is lipoprotein(a) or Lp(a)?
Lp(a) is an LDL-like particle in your blood whose level is set mostly by your genes. High Lp(a) raises the risk of heart attack, stroke, and narrowed heart valves, independent of your regular cholesterol.
How often should I test Lp(a)?
Because it's largely genetic and stable, most people only need it measured once in a lifetime. Testing is especially worthwhile if you have a family history of early heart disease.
Can you lower Lp(a) with diet or exercise?
Not much — lifestyle has little effect on Lp(a) itself because it's genetic. If yours is high, the strategy is to aggressively manage every other risk factor. Targeted drugs are also in late-stage trials.