No Blood Needed

Saliva Testing Helps Identify Patients at Risk for Heart Disease

by Teddi Fine

Due to the popularity of forensic crime-lab television shows, a vast majority of Americans know that body-fluid samples can put criminals behind bars. What most people don’t know is that measuring a certain protein, called C-reactive protein (CRP), also may help save lives.

CRP in the blood is a well-established general measure of inflammation in the body. CRP levels above an American Heart Association cut-off level, are suggestive of significant risks for cardiovascular disease.

CRP blood tests are invasive, take time, and can be costly. However, Dorothée Out, postdoctoral fellow at the Center for Interdisciplinary Salivary Bio science Research   (CISBR); Douglas A. Granger, PhD, professor and CISBR director; professor Gayle G. Page, DNSc, RN, and other colleagues from the University of Akron found that a saliva test might be just as effective and cost less. [“Assessing Salivary C-reactive Protein: Longitudinal Associations with Systemic Inflammation and Cardiovascular Disease Risk in Women Exposed to Intimate Partner Violence,” Brain, Behavior, and Immunity, in press]

According to Granger, “If CRP can be measured accurately in saliva, sampling would be stress- and pain-free, minimally invasive, and could be self-collected, lowering the barriers to having it checked for many individuals.”

In a two-year, longitudinal exploration of more than 100 women seeking help from domestic violence shelters and community agencies, the researchers collected and compared CRP samples from saliva and blood.

They found that saliva CRP measurement was accurate and precise, and that salivary and blood CRP levels were stable across a period of two years. Also, the pattern of correlations with body mass index was identical for both blood and saliva CRP measurements. Moreover, the saliva test measured women with low levels of CRP—low risk for heart disease—with the same precision as the comparable blood test. It was not as accurate as the blood test when measuring high CRP levels. Nonetheless, the implications are tantalizing. If you test with low CRP levels in oral fluid it is pretty certain you are in the “low-risk” group, but if you test high, then you would need a follow-up blood test.