C-reactive protein in the diagnosis and management of infections in granulocytopenic and non-granulocytopenic patients.

The serum levels of C-reactive protein (CRP) were assayed in 64 non-granulocytopenic and 35 granulocytopenic patients with or without fever and infection. Most patients showed a direct CRP response within 24 hours after onset of fever (95% of non-granulocytopenic patients, 100% of granulocytopenic patients). The mean peak level of CRP in febrile patients with septicemia was 207 mg/l (median 214 mg/l) in non-granulocytopenic patients and 173 mg/l (median 168 mg/l) in granulocytopenic patients, and differed significantly (p less than 0.001) from that in febrile patients without positive blood cultures. A significant difference between patients with major and minor infections was also found (p less than 0.01). No significant difference in the CRP level was found between patients with microbiologically and clinically documented infections (p greater than 0.05), nor did the serum CRP levels differ between patients with infections due to gram-positive and gram-negative organisms. The most favorable cut-off limit for detection of an inflammatory process in this study was 25 mg/l. There was no quantitative difference between CRP levels measured by a latex-agglutination method and the nephelometry assay.