(CBS/AP) Concerned about cholesterol? You may be familiar with total cholesterol, as well as HDL (good) cholesterol and LDL (bad) cholesterol. But your next checkup could add a new number to the mix.
Increasingly, doctors are going beyond standard cholesterol counts, using another test to take a closer look at the bad fats - a count of particles that carry LDL through the blood.
Cardiologists are divided over the usefulness of the approach. Some say it might help pinpoint at-risk patients who regular checks miss, or get more information about how aggressively to treat them.
But so far, major heart organizations don't recommend the extra tests, which are pricier than regular cholesterol exams (though Medicare and many other insurers pay for them). And it's not always clear what the results mean.
"I see a lot of people being confused," said Dr. Nieca Goldberg of New York University Langone Medical Center and the American Heart Association. Especially when they're used on low-risk people, "you don't know how to make sense of the information."
Yet up to half of heart patients apparently have normal levels of LDL cholesterol, and some doctors say particle testing might help find them sooner.
"For most people, the standard lipid profile is fine," said Dr. Michael Davidson of the University of Chicago. But "I get referred people who said, 'My cholesterol was fine, why do I have heart disease?' We're showing them, well, because your particle number's sky high and they were not aware that was a problem."
Davidson chaired a committee of the National Lipid Association that this month called the extra tests reasonable to assess which at-risk patients might need to start or intensify cholesterol treatment. That committee's meeting was paid for by a grant from eight pharmaceutical companies, including makers of particle tests.
Doctors have long focused on three key cholesterol numbers:
*Total cholesterol should be below 200.
*LDL (bad) cholesterol level should be below 130 for healthy people, but someone with heart disease or diabetes should aim for under 100.
*HDL (good) cholesterol is considered protective at a level of 60 or higher, while below 40 is a risk.
Where do particles come in? Scientists have long known that small, dense LDL particles "sneak" into the artery wall to build up and narrow blood vessels more easily than large, fluffy particles. While overall LDL levels usually correlate with the number of particles in blood, they don't always - just as a bucket of sand may weigh the same as a bucket of pebbles but contain more particles.
Only in recent years have commercial tests made particle checks more feasible - though there's no standard method, and different tests measure in different ways. The tests add another $100 to $150 to regular cholesterol checks.
But is knowing about your particles truly useful, and if so when? That's where doctors are split.
A study published last spring used one particle test, from Raleigh, N.C.-based LipoScience, to analyze a database of more than 5,000 middle-aged people whose heart health was tracked for five years. Most people's overall LDL and particle counts correlated well. But people had a higher risk of heart disease when their particle count was higher than their LDL predicted - and, conversely, a lower risk if their particle count was lower than expected, says lead researcher Dr. David Goff Jr. of Wake Forest University.
"We could be treating some people who don't need to be treated...and we may be missing some people who should be treated," Goff said. "But I'd also say that we haven't done all the research that needs to be done to prove that this will lead to better patient outcomes."
Many of those high-risk patients could be caught by a closer look at standard tests "for no additional charge," says Dr. Roger Blumenthal of Johns Hopkins University and the American College of Cardiology.
Triglycerides, another harmful fat, are a good indicator, Blumenthal said. You're at risk despite a low LDL if your triglycerides are over 130, not to mention a low HDL, he said. People who are obese, diabetic of borderline diabetic also are at greater risk, because they often have higher LDL particle counts.
Another way to measure without an added test: Just subtract HDL from your total cholesterol number. The resulting bad-fat total should be no higher than 30 points above your recommended LDL level - and if they are, it's time for serious diet and exercise, adds Dr. Allen Taylor of Washington Hospital Center.
WebMD has more on cholesterol management.