Pilot study evaluating C-reactive protein levels in the assessment of response to treatment of severe bloodstream infection.

We evaluated the usefulness of monitoring daily C-reactive protein (CRP) levels after initiation of antimicrobial therapy in 44 patients with bloodstream infection. The ratio of the CRP level during therapy to the level at the start of antimicrobial therapy (CRP ratio) was measured. A CRP ratio of >0.58 at day 4 of therapy was a marker of poor outcome (sensitivity, 0.89; specificity, 0.69). The recognition of a pattern of CRP-ratio response was useful in the prediction of individual clinical course.