Value of C-reactive protein testing questioned by many

Physicians' use of this cardiac risk marker ranges from routine to never, and some experts wonder whether it should be used beyond research settings.

By Victoria Stagg Elliott, AMNews staff. June 14, 2004.

When assessing heart disease risk, physicians are increasingly opting to include a test for C-reactive protein, a marker of inflammation. Some already consider it routine, although most use it mainly as a tie-breaker to determine strategies for middle-risk patients.

But is the test useful? Whether CRP testing provides insights is a question clinicians and scientists have been struggling to answer.

The question was hotly debated at last month's annual meeting of the Clinical Ligand Assay Society in Chicago. The subject also has been the focus of numerous studies. The conclusions vary.

For instance, according to a paper published in an April issue of the New England Journal of Medicine, CRP levels are only a so-so heart disease predictor, offering specificity and sensitivity comparable with a blood pressure check. Cholesterol and smoking status were the most significant risk indicators. CRP levels seemed to add little to the profile and did not change prevention strategies.

"The extra predictive information above and beyond the established risk factors is rather limited," said Dr. John Danesh, lead author and professor of epidemiology and medicine at Cambridge University in the United Kingdom. "There's no compelling reason to measure C-reactive protein at the present time, although it remains a question requiring further evaluation."

But on the other side, a study of 27,000 healthy American women published in the Nov. 14, 2002, NEJM amplified what many smaller studies had concluded for years -- that CRP could be used to identify many more people who were at risk for cardiovascular events.