CRP/ESR disagreement common in infection, inflammation

(HealthDay)—For patients with suspected infection or inflammation, C-reactive protein (CRP)/erythrocyte sedimentation rate (ESR) disagreement is common, according to a study published online Dec. 31 in the International Journal of Rheumatic Diseases.

Stephanie Sbong, M.D., and Mark Feldman, M.D., from the Texas Health Presbyterian Hospital in Dallas, examined simultaneously ordered CRP and ESR results for 70 adult patients with suspected infection or inflammation. The authors examined CRP/ESR disagreements and their stability in repeat testing in adults who had been tested on three separate occasions.

The researchers found that in 20 percent of patients there were initial CRP/ESR disagreements. Of these 14 patients, only four had stable disagreements throughout the study, while 10 patients later exhibited CRP/ESR agreements. Of the 56 patients with initial CRP/ESR agreement, on subsequent testing, 10 developed CRP/ESR disagreements.

"Three mechanisms were identified to explain CRP/ESR disagreements: (i) slight fluctuations in the CRP and ESR around the upper limits of normal for these tests; (ii) development of an intercurrent illness; and (iii) different time courses of CRP and ESR elevations, in which the CRP rose and fell faster than the ESR," the authors write.