Point-of-caRE DiagnostICs for respiraTOry tRact infectionS (PREDICTORS) study: developing guidance for using C-reactive protein point-of-care tests in the management of lower respiratory tract infections in primary care using a Delphi consensus technique.

Objective: Antimicrobial resistance is a significant global health challenge, exacerbated by unnecessary antibiotic prescribing. Respiratory tract infections (RTIs) are common reasons for antibiotic prescribing in primary care, despite most being viral or bacterial infections that are self-limiting. C-reactive protein (CRP) point-of-care tests (POCTs) are promising tools to support antibiotic stewardship by guiding the management of lower RTIs (LRTIs). The aim of this study was to develop best practice guidance for using CRP POCT in the management of LRTIs in primary care.

Design: Scoping review findings informed guidance statements, which were then evaluated through a three-round Delphi process with an expert panel via web-based questionnaires. Statements focused on intended use, detection of bacterial LRTIs, communication strategies, device features, performance and ease of use of CRP POCT.

Setting and participants: The panel of experts included 19 healthcare professionals across several specialties, including general practitioners, community pharmacists, hospital pharmacists and respiratory physicians.

Main outcome measures: Panellists rated each guidance statement using a 5-point Likert scale, with acceptance, revision or rejection determined using predefined cut-off scores for medians and interquartile ranges. Statements were revised between rounds using the feedback provided by panellists.

Results: In the first round, 49 statements were evaluated; 16 were accepted, nine removed and 24 revised for the second round. Of the 24 statements evaluated in the second round, 17 were accepted and seven were revised. In the third round, consensus was reached on four of the seven statements presented, resulting in 37 final guidance statements. These statements covered key areas, including the appropriate use of CRP POCTs to guide antibiotic prescribing, CRP cut-off values, integration with clinical decision rules, device performance and operational considerations, training requirements and financial reimbursement. The panel emphasised the need for structured guidelines to align CRP POCT use with clinical context and highlighted its role in improving diagnostic confidence while supporting antibiotic stewardship.

Conclusions: This study provides a set of best practice guidance statements to support the use of CRP POCT in the management of LRTIs in primary care. Dissemination and further research are required to assess their impact.