What's the Usefulness of CRP Testing?
Measuring C-reactive protein in the blood may -- or may not -- indicate that a person is at risk for heart disease.
CRP Test Not Recommended for Everyone
If you've got other risk factors for heart disease, you're most likely already taking a cholesterol-lowering drug and aspirin therapy, and are on lifestyle-changing programs such as routine exercise and weight loss to prevent heart disease.
"Knowing your CRP level in this case wouldn't change a doctor's recommendations," Robert Ostfeld, MD, MS, tells WebMD. Ostfeld is a cardiologist at Montefiore Medical Center in Brooklyn, N.Y. Statin drugs as well as standard lifestyle changes used to lower cholesterol have been shown to lower CRP levels as well, but it's not clear that having a high CRP level yet having other factors that only place you at a "low to moderate" risk for future heart disease warrants treatment with a statin. An ongoing study known as the JUPITER trial is trying to address this very issue.
CRP testing might be useful when a doctor is undecided about how aggressively to treat a patient who is considered to be at 'intermediate' risk for a heart attack (meaning having a 10% to 20% risk for heart attack in the next 10 years based on his or her health status and history). In such a case, elevated CRP levels might cause a doctor to decide on more intensive treatment than he would have without CRP results.
Currently, CRP testing is not recommended for the general population. "But it's being pushed and pushed, and people are being led into believing that CRP is a lifesaver for everybody and it's just not," says Shah, who routinely receives requests from his patients for the test. "Patients are often misled into believing that all of a sudden there's this unique marker that's going to determine whether they live or die."
Shah calls the test an interesting but not yet clinically usable tool. "If future studies show that even if all other risk factors are under good control but CRP is high and that that lowering CRP is going to create clinical benefit, then there would be a reason to measure CRP, but we don't have that information yet," he says.