What the lipoprotein(a) test shows
Lipoprotein(a) — written Lp(a), said “L-P-little-a” — is a low-density lipoprotein (LDL) particle carrying an extra protein, apolipoprotein(a); the test measures its blood level. A standard panel estimates the cholesterol inside particles, but Lp(a) is one specific, genetically driven particle that is both atherogenic (plaque-forming) and pro-thrombotic (clot-promoting). MedlinePlus calls it a type of LDL that can raise heart-disease and stroke risk even when routine cholesterol looks fine.
It differs from its neighbours. LDL cholesterol measures the cholesterol inside ordinary LDL — and a standard LDL value already includes the cholesterol Lp(a) carries, so a high Lp(a) can quietly inflate it. ApoB counts all atherogenic particles, but Lp(a) is only a small share, so a normal apoB does not rule out high Lp(a). The American Heart Association stresses that Lp(a) is an independent, causal risk factor; being 70–90% genetic, it stays stable for life, so one test usually suffices.
Lipoprotein(a) normal range
Lp(a) has no true “normal range” — risk climbs continuously with the level, so results are read against risk thresholds. Two units are used and they are not interchangeable: mass units (mg/dL) weigh the particle, molar units (nmol/L) count particles. The old mg/dL × 2–2.5 conversion is now discouraged as unreliable; molar (nmol/L) reporting on an isoform-insensitive assay is preferred.
| Risk band | Conventional (mg/dL) | Molar (nmol/L) |
|---|---|---|
| Low risk (desirable) | < 30 | < 75 |
| Gray zone / borderline | 30–50 | 75–125 |
| High risk | > 50 | > 125 |
| Very high (FH-like risk) | > ~180 | > ~430 |
These cut-offs — used by the ACC and the European Atherosclerosis Society — apply to adults of any sex. Unlike most lipids, Lp(a) barely shifts with age (levels are largely set by about age 5), rising only modestly after menopause; ancestry matters more than sex. Assays and ranges vary between labs, so read your result against your own report.
Why lipoprotein(a) is high
A high Lp(a) is common — roughly 1 in 5 people worldwide are above the high-risk threshold — and the cause is usually genetic. By frequency:
- Inherited (by far the commonest). The LPA gene sets the level and passes down directly, so Lp(a) can be high while LDL cholesterol, HDL cholesterol and triglycerides all look perfect.
- Ancestry. Levels run higher in people of African and South Asian descent.
- Secondary (minor) causes. Chronic kidney disease or nephrotic syndrome, an underactive thyroid, and the fall in estrogen after menopause can each nudge Lp(a) up — so creatinine and TSH are useful cross-checks.
A high Lp(a) is a lifelong risk multiplier, not an emergency. But a very high level with a strong family history of early heart attack or stroke, or established cardiovascular disease, warrants prompt risk assessment — every ~50 nmol/L rise adds about 11% to cardiovascular risk, per a 2025 Cleveland Clinic review.
Why lipoprotein(a) is low
A low Lp(a) is good news — lower cardiovascular risk and no symptoms. It usually reflects inherited genes: larger apolipoprotein(a) forms make less of the particle. Less often it is secondary to:
- Overactive thyroid (hyperthyroidism).
- Advanced liver disease, since the liver makes apolipoprotein(a) and serious injury cuts production — one reason ALT may be read in context.
- Certain drugs, including estrogen, niacin and PCSK9 inhibitors.
A low Lp(a) needs no treatment; the clinically important question is almost always a high result.
What to test alongside
Lp(a) is best read with the rest of the lipid panel and a few metabolic checks:
- LDL cholesterol — the main treatment target.
- ApoB — total atherogenic particle count.
- Total cholesterol and HDL cholesterol — the rest of the standard panel.
- Triglycerides — completes the lipid profile.
- Apolipoprotein A1 — the main protein of protective HDL.
- Cholesterol ratio — a summary of the balance.
- hs-CRP — inflammatory risk.
- HbA1c and glucose — a diabetes screen.
- TSH and creatinine — thyroid and kidney checks; both can raise Lp(a).
See also the guide to understanding your lipid panel.
What to do about an abnormal result
- Don’t panic, and don’t self-treat. A high Lp(a) is a common inherited trait, not an acute problem, and no supplement reliably lowers it.
- Confirm a borderline number. Ask for a repeat on a molar (nmol/L), isoform-insensitive assay, and check whether a thyroid or kidney issue is inflating it.
- Lower everything you can change. Because Lp(a) is hard to move, the proven response is to cut other risk: reach the LDL cholesterol / apoB target (statin, ezetimibe or a PCSK9 inhibitor), treat blood pressure and blood sugar, and stop smoking.
- Think about family. Because it is genetic, first-degree relatives may benefit from their own Lp(a) test — cascade screening.
- See the right doctor. Start with primary care; a very high level, early cardiovascular disease or a strong family history is reason to refer to a cardiologist or lipid specialist. As of 2026 no drug is approved specifically to lower Lp(a), though targeted therapies (pelacarsen, olpasiran) are in phase 3 outcome trials, with the first results — from pelacarsen’s Lp(a) HORIZON trial — expected in 2026.
Mini-FAQ
Is there a normal range for lipoprotein(a)?
There is no classic normal range — risk rises continuously with the level. Most guidelines treat below 30 mg/dL (75 nmol/L) as low risk and 50 mg/dL (125 nmol/L) or above as high risk, with a gray zone in between.
Why is my lipoprotein(a) high when the rest of my cholesterol is normal?
Because Lp(a) is set almost entirely by your genes, not by diet or lifestyle, it can be high even with a perfect LDL, HDL and triglyceride profile. About 1 in 5 people carry an elevated level.
Can diet or exercise lower lipoprotein(a)?
Not meaningfully. Unlike LDL, Lp(a) barely responds to diet, exercise or statins. As of 2026 no drug is approved specifically to lower it, though targeted therapies are in late-stage trials.
How often should lipoprotein(a) be tested?
Because the level is genetic and stays stable through life, most experts recommend measuring it once in every adult’s lifetime. A repeat is only needed if the first result was borderline or a new factor appears, such as kidney disease or a thyroid change.
Does a high lipoprotein(a) mean I will have a heart attack?
No. It raises the risk but does not guarantee an event. It multiplies your overall cardiovascular risk, so the response is to lower everything you can change — LDL/apoB, blood pressure, smoking and blood sugar.
What is the difference between lipoprotein(a) and LDL cholesterol?
LDL cholesterol measures the cholesterol inside ordinary LDL particles; Lp(a) is a distinct, sticky LDL-like particle with an extra protein that also promotes clotting. A standard LDL result can look healthy while Lp(a) is high.
