Immediate Availability of C-Reactive Protein and Leukocyte Count Data Influenced Physicians' Decisions to Prescribe Antimicrobial Drugs for New Outpatients with Acute Infections (Technical Briefs‪)‬

Physicians often prescribe antibiotics to febrile patients despite a lack of evidence of bacterial infection (1-5). C-Reactive protein (CRP) and leukocyte count [white blood cell count (WBC)] can contribute to differentiation of possible bacterial vs viral infections (6) because patients with acute bacterial infections typically have markedly increased CRP and WBC whereas patients with viral infection do not. Other studies (7-9) have also suggested the potential value of CRP with WBC in patients with infections or inflammatory conditions. We studied the potential usefulness of immediate testing for CRP and WBC in physicians' decisions to prescribe antimicrobial drugs for acutely febrile new outpatients. This study was carried out in the mornings in a primary care setting. Among all new outpatients who visited the General/ Internal Medicine Clinic of Nishi-Ohmiya Hospital (a regional/ community 150-bed hospital treating ~500 outpatients per day), 305 patients presenting with fever ([greater than or equal to] 37.5[degrees]C) 8 days in duration and suspected of having infection were entered in this study. Eleven physicians, ages 29-53 years with 5-29 years of experience, participated in patient clinical examination during the study period from December 2000 to January 2003. Three physicians were full-time members of the hospital staff. Patients were randomized by a study controller into two groups irrespective of symptoms. As illustrated in Fig. 1 in Data Supplement 1, which accompanies the online version of this Technical Brief at http://www.clinchem. org/content/vol50/issuel/, one group (147 patients) underwent CRP and WBC testing before the physician's initial clinical examination (advance testing group), and physicians made the initial clinical diagnosis and management decisions after test results were reported. The other group (154 patients; without advance testing group) did not receive tests before the initial clinical examination, and diagnoses and management decisions were based on history and physical examination unless urgent tests were ordered. The numbers of patients with and without advance testing for each physician were nearly equal, except for a few physicians who saw few patients. The study design did not restrict in either patient group urgent testing considered necessary by the physician. The results of nonurgent tests ordered at the initial clinical examination (additional or subsequent tests) were evaluated at the patient's next visit. All patients were informed of the study design and registered only after providing written informed consent to the study. The protocol was approved by the hospital's Clinical Study Committee.