INTRODUCTION: The aim was to assess whether the frequency of antibiotic prescriptions to patients with respiratory infections is reduced when general practitioners (GPs) use a CRP rapid test to support their clinical assessment, and to examine whether the use of the test would have any effect on the course of disease.

MATERIAL AND METHOD: A randomised controlled trial was carried out by 35 general practices in the County of Funen, Denmark, with 812 patients with respiratory infection. The main outcome measures were frequency of antibiotic prescriptions and morbidity one week after the consultation, as stated by the patients.

RESULTS: The frequency of antibiotic prescriptions was 43% (179/414) in the CRP group and 46% (184/398) in the control group (NS, OR = 0.9). At one week, increased or unchanged morbidity was stated more frequently in the CRP group (12%) than in the control group (8%) (OR = 1.6, p = 0.05). In the control group, the variable having the greatest influence on whether the GP prescribed antibiotics was the patient's general well-being (OR = 2.9, p < 0.0001), whereas in the CRP group the CRP value had the greatest influence (OR = 1.1 per unit increase [mg/l], p < 0.0001).

CONCLUSION: From on the present study, the use of a single CRP rapid test to support possible antibiotic treatment of respiratory infections in general practice cannot be recommended.