Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

OBJECTIVES: This study aims to investigate C reactive protein (CRP) testing practices in paediatric ambulatory care across British primary care and accident and emergency (A&E) departments. DESIGN, SETTING, PARTICIPANTS: This retrospective cohort study included children <18 years old having ≥1 CRP test at primary care or A&E departments in Oxfordshire between 2007 and 2021. OUTCOMES: We estimated the frequency and annual changes in CRP testing in both settings and evaluated referral and admission patterns based on CRP levels: low (<20 mg/L), intermediate or high (≥80 mg/L). RESULTS: Over 15 years, 91 540 CRP tests were requested in 63 226 children, with 33 882 (53.6%) in primary care and 29 344 (46.4%) in A&E. Both settings showed rising trends in test requests, with average annual percentage change of 3.0% (95% CI 1.2% to 4.7%) in primary care and 11.5% (95% CI 8.6% to 14.6%) in A&E. The proportion of intermediate/high-test results remained stable. In primary care, 50 709 (95.8%) of CRP tests were <20 mg/L, with 99.0% of these children managed at home. High and intermediate CRP values increased odds of referral versus low CRP (OR adjusted for age=21.80; 95% CI 16.49 to 28.81 and 4.77; 3.78 to 6.02, respectively). At A&E, 27 610 (71.5%) children had CRP<20 mg/L, of whom 42.5% were admitted while 3776 (9.8%) had CRP≥80 mg/L with 57.9% admission rate. High and intermediate CRP values increased odds of admission versus low CRP (OR adjusted for age=1.90; 95% CI 1.78 to 2.04 and 1.39; 1.32 to 1.46, respectively). CONCLUSION: There are rising trends of CRP test requests in paediatric ambulatory care settings, with no evidence of increases in proportion of intermediate/high-test results in primary care. Low CRP values at primary care were linked to children managed at home, while almost half of children with low CRP values at A&E were admitted to the hospital.

Original publication




Journal article


BMJ Open

Publication Date





ACCIDENT & EMERGENCY MEDICINE, EPIDEMIOLOGY, PAEDIATRICS, Humans, C-Reactive Protein, Retrospective Studies, Child, Child, Preschool, Female, Male, Primary Health Care, Adolescent, Ambulatory Care, Infant, Referral and Consultation, Emergency Service, Hospital, Infant, Newborn, England