Lipoprotein(a)
Also called Lp(a), lipoprotein little a
Lipoprotein(a), usually written Lp(a) and said "L-P-little-a," is a cholesterol-carrying particle built like LDL with an extra protein attached. Like LDL it deposits cholesterol in artery walls, and it also supports blood clotting, which helps explain why a high level is linked to heart attack, stroke, heart valve disease and narrowed arteries in the legs.
What sets Lp(a) apart is that genes, not diet or exercise, largely decide the level. It changes little in response to lifestyle, so for most people a single measurement is considered enough. A standard cholesterol panel does not report it: a person can have an ordinary LDL result while a large share of that LDL is carried as Lp(a). Lp(a) is also not a routine screening test in the US, and researchers are still studying when it should be used. What a result means and what it changes is covered in Lp(a): The Inherited Risk Factor You Test Once.
Why it matters after 45
Midlife is when most people first look seriously at their cardiovascular risk, and Lp(a) is the piece a routine panel leaves out. In the US, testing is recommended for people under 65 who have had a heart attack, people with a family history of early heart disease, and people whose LDL stays high despite cholesterol-lowering medicine. A high Lp(a) raises risk without making an event inevitable, which is why it tends to shape how firmly the other, modifiable risks are managed.
Where it comes up
References
- MedlinePlus. Lipoprotein (a) Blood Test. U.S. National Library of Medicine. https://medlineplus.gov/lab-tests/lipoprotein-a-blood-test/
- National Heart, Lung, and Blood Institute. Lipoprotein(a): What to know about elevated levels, 2024. https://www.nhlbi.nih.gov/news/2024/lipoproteina-what-know-about-elevated-levels
Definitions here are educational and are not medical advice. They explain what a term means; the pages linked above cover what it means for you, and a clinician reviews your own results. Editorial & medical review policy · All glossary terms