Objective

To assess whether the frequency of antibiotic prescriptions to patients with respiratory infections is reduced when general practitioners (GPs) use a C-reactive protein (CRP) rapid test in support of their clinical assessment, and to study whether using the test will have any effect on the course of disease

Design

Randomised controlled trial.

Setting

35 general practices, County of Funen, Denmark.

Patients

812 patients with respiratory infection.

Main Outcome Measures

Frequency of antibiotic prescriptions and morbidity 1 week after the consultation, as stated by the patients.

Results

In the CRP group the frequency of antibiotic prescriptions was 43% (179/414) compared with 46% (184/398) in the control group (odds ratio (OR) = 0.9, NS). After 1 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 patients’ 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

Based on the present study, the use of the CRP rapid test in support of a possible antibiotic treatment for respiratory infections in general practice cannot be recommended.