Lp(a) (Lipoprotein(a)): what this marker means

What is Lp(a) (Lipoprotein(a))?

Lp(a), or Lipoprotein(a), is a specific lipoprotein particle that circulates in the blood. It consists of a low-density lipoprotein (LDL) core with a unique protein attached to it called apo(a). This protein is structurally similar to plasminogen, an enzyme involved in the breakdown of blood clots. This structural similarity is precisely why Lp(a) can interfere with the natural dissolution of clots and promote atherosclerosis, the thickening and hardening of arterial walls.

Lp(a) concentration in the blood is largely determined by genetics. This means that dietary changes, physical activity, and other lifestyle factors that effectively influence other lipid markers do not significantly change this one. For this reason, Lp(a) is assessed separately from other lipid panel markers.

It is measured in nmol/L or mg/dL. It is important to know which unit your laboratory uses, as the reference ranges differ between units.

Reference ranges

In most laboratories, blood Lp(a) concentration is considered acceptable when it does not exceed 75 nmol/L (or approximately 30 mg/dL). Some countries and laboratories use slightly different thresholds, so always refer to the reference range provided by your own laboratory.

It is worth noting that Lp(a) distribution in the population is not uniform. About 20% of people have a genetically elevated Lp(a) level. This marker remains fairly stable throughout life, so repeat measurements are generally not necessary unless there are specific clinical indications.

Why it may be elevated

A high Lp(a) level is most often genetically determined. It is passed down from generation to generation and is not linked to lifestyle. The underlying mechanism involves inheriting specific variants of the LPA gene that lead to increased production of the apo(a) protein.

Although lifestyle does not directly change this marker, certain clinical conditions can temporarily raise Lp(a) concentration: kidney insufficiency, hypothyroidism (reduced thyroid function), and certain other illnesses. Women going through menopause may also notice a rise in Lp(a) due to changes in estrogen levels.

Elevated Lp(a) is considered an independent cardiovascular risk factor. This means that even with normal cholesterol values, an elevated Lp(a) may indicate a higher risk.

Why it may be low

A low Lp(a) level is generally not clinically significant and is not considered a problem. A low result is actually favorable, as it is associated with lower cardiovascular risk.

When interpreting very low Lp(a) values from a laboratory, it may occasionally be worth considering whether the marker was measured accurately, since methods can differ slightly between laboratories. From a clinical standpoint, however, low Lp(a) requires no action.

What to do next

If your Lp(a) level is elevated, the most important step is to discuss the result with your doctor. Although direct options for lowering Lp(a) are currently limited, your doctor can evaluate your overall cardiovascular risk and suggest appropriate preventive measures.

You can actively manage other cardiovascular risk factors: blood pressure, total cholesterol, blood sugar, body weight, and smoking. Even if these do not directly change Lp(a), they can significantly reduce overall risk.

Family history also matters. If close relatives had early heart disease, it is worth informing your doctor.

Monitoring over time

Because Lp(a) is genetically determined and does not change meaningfully over a lifetime, repeat measurement is generally not necessary. Most guidelines recommend measuring Lp(a) at least once in a lifetime, especially for those with a family history of early heart disease or whose other lipid markers are concerning.

If you already know your Lp(a) level is elevated, continue monitoring other cardiovascular markers: the full lipid panel, blood pressure, glucose, and inflammatory markers.

Questions for your doctor

To prepare for your appointment, you may want to consider the following questions:

• What is my overall cardiovascular risk profile given my Lp(a) result?
• Should my close relatives be tested for elevated Lp(a)?
• Which lifestyle changes would most reduce my overall risk?
• Will I need to repeat this test in the future?
• Are there additional tests that would help better assess my heart health?

This is not medical advice. Please consult your doctor for health-related decisions.