Serum C-reactive protein levels in the management of infection in acute leukaemia.

C-reactive protein (CRP) was measured serially in 29 patients with acute leukaemia. Sixty-four febrile episodes (greater than or equal to 38 degrees C) occurred during 37 periods of neutropenia (less than 0.5 X 10(9)/l). In all of 41 microbiologically or clinically documented infections the maximum CRP level exceeded 30 mg/l, and in 25 it was greater than 100 mg/l. In no case in which the CRP level remained below 30 mg/l for 48 hr after the onset of fever was any clinical or microbiological evidence of infection obtained. The CRP level during documented infection began to fall 24-48 hr after appropriate treatment was begun. A CRP level above 30 mg/l in neutropenic patients was associated with early recurrence of fever if systemic antibiotics were discontinued. Graft-vs-host disease, without infection, did not result in high levels of CRP.