This Test May Be a Better Indicator of Heart Disease Risk

February is American Heart Month, when people are encouraged to pay extra attention to their cardiovascular health. Getting your cholesterol levels checked is a key part of that process—but is a standard lipid blood test enough to accurately assess your heart disease risk?

During a typical cholesterol test, healthcare providers draw a patient’s blood and assess their levels of high-density lipoprotein (HDL), or “good” cholesterol, as well as low-density lipoprotein (LDL), or “bad” cholesterol. High levels of LDL cholesterol and low levels of HDL cholesterol are usually indicative of a higher heart disease risk.

But some experts argue that this conventional test might miss heart disease red flags in certain people. Instead, measuring the levels of apolipoprotein B (ApoB) in a person’s blood might be more accurate, they say.

APoB is a structural protein found in troublesome cholesterol, including LDL. It’s also found in very low-density lipoproteins (VLDL) and intermediate-density lipoproteins (IDL), which also raise heart disease risk.

But traditional lipid panel tests don’t pick up VLDL and IDL cholesterol levels, explained Ann Marie Navar MD, PhD, cardiologist and associate professor of internal medicine and population and data sciences at UT Southwestern Medical Center.

Navar and her colleagues conducted a study, published this past summer in JAMA Cardiology, to investigate how ApoB and standard cholesterol tests compared to one another. After looking at data from over 12,000 adults who took both tests, the researchers found that seemingly healthy people can still have a high concentration of ApoB particles despite having normal LDL cholesterol levels.

“In those situations, as clinicians, we can get tricked into thinking that our patient’s cholesterol is under control,” Navar told Health. “But in reality, their high [non-HDL] cholesterol levels remain undetected, putting them at a greater risk of developing atherosclerosis” (plaque buildup in the arteries).

So the next time you visit your doctor’s office, should you ask for an ApoB test over a traditional lipid panel? Here’s what experts had to say.

Because the ApoB test is able to pick up on VLDL and IDL cholesterol levels, it’s clearly more sensitive than a traditional lipid panel, which simply measures the overall weight of LDL cholesterol particles. But not everyone needs their cholesterol broken down this specifically.

“For most people, how much cholesterol they have in their LDL particles by weight correlates very highly with how many ApoB particles they have,” Navar explained.

Essentially, doctors can be sure that a person has an elevated risk of heart disease if they have a high LDL cholesterol reading on a standard lipid panel, she said. An ApoB test isn’t needed.

“The lipid blood test is good enough for the majority,” said Navar.

However, certain people have a condition known as discordance, which means they have normal LDL cholesterol readings but a high amount of ApoB particles.

People with metabolic diseases, such as obesity or diabetes, are more likely to have this discordance. However, the authors of the JAMA Cardiology study noted that “significant variability in ApoB levels was observed even among metabolically healthy individuals.”

As a preventive cardiologist who has conducted lipids research for several years, Navar said she advises her patients to opt for an ApoB blood test.

“There can be measurement errors in an LDL cholesterol test, especially when a patient is either in the high or low ranges of LDL,” she said. “ApoB is much less affected by measurement errors than LDL cholesterol and can be useful to determine if patients with discordance require medication.”

Another pro is that people don’t need to fast to get their ApoB measured, which is sometimes the case for the traditional cholesterol test, Navar added.

However, that doesn’t necessarily mean that the traditional lipid panel needs to go by the wayside.

“While the study findings are robust, I do not think an ApoB test is superior,” Seth Martin, MD, director of the Advanced Lipid Disorders Program and professor of cardiology at Johns Hopkins University, told Health. “Instead, this analysis shows significant discordance within patients and highlights the importance of patients getting both tests done to rule out high cholesterol.”

Though ApoB may be the more accurate test—particularly for people with metabolic issues or others who may have discordance—there are some issues with the test in practice.

For one, Martin said, most labs charge $20 or $30 for an ApoB test, which can be a barrier for people.

Even simply finding the test can be a challenge, as not all labs perform ApoB evaluations, he added.

“There is a disconnect between studies like the one in JAMA Cardiology and groups of experts and real-world clinical practice,” Martin explained. “Most clinicians are unfamiliar with ApoB and non-HDL measures.”

Currently, there’s a lack of guidance on what constitutes a high or low ApoB reading in patients, Navar added. Some research categorizes ApoB concentrations of 130 milligrams per deciliter or greater as unhealthy, though other research puts that figure lower, closer to 105 milligrams per deciliter, for example.

Overall, “the medical community needs more guidance before we can expect more general practitioners and internal medicine clinicians to start using the ApoB test more broadly,” Navar said.

The vast majority of healthcare providers prefer standard lipid panel tests. However, it’s worth bringing up ApoB testing with your clinician, especially if you have a condition such as diabetes or obesity, but your cholesterol levels appear normal on standard blood tests.

Of course, using ApoB to paint a fuller picture of someone’s heart disease risk is only helpful if they are also open to medication and lifestyle interventions to lower their cholesterol levels, Navar emphasized.

Even cholesterol itself “is only one piece of the puzzle” when it comes to heart disease prevention, she added. Managing blood pressure and blood sugar levels are also key, in addition to maintaining a healthy weight, staying active, and sticking with a treatment plan from your healthcare provider.