Agreement between erythrocyte sedimentation rate and C-reactive protein in hospital practice.

BACKGROUND: Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are frequently prescribed jointly. The usefulness of this practice is uncertain. METHODS: All patients with ESR and CRP measured at the same time in an academic tertiary hospital during a 1-year period were included. Concomitant measures of serum creatinine, hematocrit, and anti-Xa activity were recorded to study noninflammatory cause of increased ESR. Level of agreement between ESR and CRP was assessed with kappa coefficient, and their accuracy was determined in a medical chart review of 99 randomly selected patients with disagreement between both markers. RESULTS: Among 5777 patients, 35% and 58% had an elevated CRP and ESR, respectively. ESR and CRP were in agreement in 67% of patients (both elevated in 30%, both normal in 37%). A disagreement was observed in 33% (elevated ESR/normal CRP in 28%, normal ESR/elevated CRP in 5%). The kappa coefficient showed poor agreement (k=0.38) between both markers. Review of medical chart showed that 25 patients with elevated CRP and normal ESR had an active inflammatory disease (false-negative ESR). Conversely, 74 patients had elevated ESR and normal CRP-32% had resolving inflammatory disorders, 28% disclosed a variable interfering with the ESR measure (false-positive ESR), 32% had unexplained discrepancies, and 8% had an active inflammatory disease (false-negative CRP). CONCLUSION: In hospital practice, joint measurement of ESR and CRP is unwarranted. Because of slow variation and frequent confounding, ESR is frequently misleading in unselected patients. When an inflammatory disorder is suspected, priority should be given to CRP.

Relevance of routine use of the anaerobic blood culture bottle.

Using the BacT/Alert automated system, we conducted a 1-year retrospective study on blood cultures, focusing on the relevance of routine use of the anaerobic bottle. The rate of patients with positive blood cultures was 19.7%. Among these, 13.5% had a positive anaerobic bottle in the absence of any aerobic bottle, and 2/3 of these grew with nonobligate anaerobes. These patients were hospitalized in 20 out of 26 wards of the hospital group. For 65.4% of the monomicrobial-positive blood cultures growing Enterobacteriaceae, the anaerobic bottle detected growth earlier than the corresponding aerobic bottle. These data suggest that, in our institution, the use of an anaerobic bottle is still relevant.