The Lp(a) test, and why once is usually enough

What the test is

Lp(a) is a particle similar to LDL, the main carrier of cholesterol, with an extra protein attached. Most cholesterol-carrying particles carry a similar risk particle for particle, and Lp(a) is one of the exceptions [1]. Studies of hundreds of thousands of people show that higher levels are linked to heart attack and stroke [2]. High levels also make narrowing of the aortic valve more likely [2].

More than 90% of the variation in Lp(a) between people is inherited, and adult levels are usually reached by about age 5 [2]. In one Copenhagen study, people above the 95th percentile had 2.6 times the rate of heart attack of those with the lowest levels [3].

Why it is done and who it is for

The 2022 European Atherosclerosis Society consensus recommends measuring Lp(a) at least once in every adult, preferably with the first cholesterol test [2]. The 2021 Canadian guideline makes the same recommendation, once in a lifetime as part of first lipid screening [4].

It is most useful if you have early heart disease in the family, a known high Lp(a) in a parent or sibling, familial hypercholesterolaemia, or heart disease despite good cholesterol results [2].

Who it is not for

If you have already had a reliable Lp(a) result, repeating it rarely adds anything, because repeated measurement does not improve risk prediction unless an illness such as kidney disease or an acute infection has changed the level [2].

A blood test is the wrong first step for chest pain, sudden breathlessness, fainting or signs of a stroke. In the UK call 999, and elsewhere call the local emergency number.

Benefits and limitations

The benefit is knowing a lifelong risk factor early enough to act on the ones you can change. A high result explains why heart disease may run in a family where cholesterol looked normal.

One limitation is that lifestyle changes have little effect on the level itself [2]. When the 2022 consensus was written, no medicine was licensed to lower Lp(a) specifically, and trials of such treatments were still awaited [2]. Results are reported in mg/dL or nmol/L, and the consensus advises against converting between them with a standard factor because laboratory methods vary [2].

Risks

The blood draw is low risk, with a small chance of a bruise or feeling faint. The main consideration is what a result means for you and your family. A high value can cause worry, and it can lead to a conversation about statins earlier than you expected. The doctor explains this before you decide.

How you prepare and what to expect

No special preparation is needed for Lp(a). If the same draw includes fasting glucose or insulin you will be told to fast. A clinician takes one sample from your arm in a few minutes, and you can return to your day straight afterwards.

Results and what a high result changes

The consensus suggests below 30 mg/dL (75 nmol/L) rules out Lp(a) as a meaningful risk, and above 50 mg/dL (125 nmol/L) rules it in, with a grey zone between [2]. Very high levels, above 180 mg/dL (430 nmol/L), carry a lifetime risk similar to untreated familial hypercholesterolaemia [2].

A high result changes how hard and how early the doctor works on everything else. The consensus recommends earlier, more intensive management of LDL cholesterol, blood pressure, glucose and lifestyle, guided by your overall risk [2]. Its modelling suggests that a lifelong LDL cholesterol about 0.5 mmol/L lower can offset roughly 120 nmol/L of extra Lp(a) [2]. NICE allows a statin even when the 10-year risk score is below 10% if there is concern the score underestimates your risk [5]. If you already take a statin, keep taking it, because its benefit far outweighs any small rise in Lp(a) [2].

Testing your family

Because Lp(a) is inherited, the consensus considers it reasonable to test a parent, brother, sister or child of someone with a markedly high level [2]. Where a family has familial hypercholesterolaemia, NICE recommends DNA testing of relatives, starting with the closest and widening where possible [6], and the consensus suggests adding Lp(a) to that testing [2].

• Is my Lp(a) low enough to rule out extra risk, or high enough to add to it?
• How does it change my overall risk, and my targets for LDL cholesterol and blood pressure?
• Should my parents, brothers, sisters or children be tested?
• Do I need a repeat test, and if so, why?

How The Wellness can help

Longevity+ measures Lp(a) and ApoB with a full profile, and a doctor calls you to go through a written plan. Samples go to accredited laboratories, and every result is explained by a GMC registered doctor at our clinics on Baker Street in Marylebone or Eccleston Street in Belgravia.

If your family lives elsewhere, appointments are arranged with partners in 12 city pages beyond London, so relatives can be tested near home.