Study background: Lower respiratory tract infections are one of the main areas where antibiotics are overused in primary care. Most of these infections are caused by viruses, which antibiotics are ineffective against. C-reactive protein (CRP) is a marker of acute inflammation, and its levels can help to distinguish between bacterial and viral infections. However, simply providing a testing tool may not be sufficient to change physicians’ deeply ingrained prescribing habits.

Study objectives: To evaluate whether providing primary care physicians with point-of-care testing for C-reactive protein, combined with communication skills training, can safely reduce antibiotic prescriptions for adult patients with lower respiratory tract infections. The study also aims to distinguish the respective contributions of the test itself and the communication training.

Type of clinical research

Intervention groups (four groups, factorial design)

1. CRP Testing Group: Physicians use a desktop CRP point-of-care analyzer to collect a finger-prick blood sample, with results available in approximately three minutes. The test results include guidance for interpreting results by range guidelines (<20 mg/L means bacterial infection not considered; 20–50 mg/L means possible; >50 mg/L means high likelihood of bacterial infection.

2. Communication Skills Training Group: Physicians receive intensive communication training based on the 'Engage-Empathize-Inform' model to manage patient expectations.

3. Combined CRP Testing and Communication Training Group: Participants receive both of the above interventions.

4. Control group: Participants receive routine clinical care only, with no additional testing or training provided.

Outcome measures

Primary endpoint: The antibiotic prescription rate at the initial visit.

Secondary endpoints: Antibiotic use one week and four weeks after the visit; Patient satisfaction; Recovery status; Readmission rate, and so on.

At the one-week and four-week follow-up visits, there were no statistically significant differences between the groups in terms of time to symptom resolution, rate of return visits, hospitalisation rate or patient satisfaction. This shows that reducing antibiotic use is safe and does not delay treatment or lower patient satisfaction.

Factor analysis confirmed that the CRP rapid test and communication training have an independent effect on reducing prescription rates and that, when combined, they have a synergistic effect. Physicians' decision-making confidence increased, and patients were more likely to accept the recommendation to 'forgo antibiotics' because they received an objective explanation of their inflammation markers.

This study confirms that introducing C-reactive protein (CRP) point-of-care testing in primary care is safe, effective and acceptable. It transforms antibiotic prescribing decisions, which are usually based on experience, into shared decisions grounded in objective measures of inflammation. Combining CRP testing with brief training in communication skills can reduce the antibiotic prescribing rate from 67% to 23% without compromising patient outcomes.

The study provides a solid evidence base for the use of CRP point-of-care testing in managing respiratory tract infections and has led to its inclusion in primary care guidelines in multiple countries as a vital tool for antimicrobial stewardship.

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