C-Reactive Protein Level as Diagnostic Marker in Young Febrile Children Presenting in a General Practice Out-of-Hours Service

Abstract

Background: It is unclear how well a C-reactive protein (CRP) value predicts a serious infection (SI) in young febrile children in general practice.Methods: This prospective cohort study with 1-week follow-up included children, aged 3 months to 6 years, presenting with fever to a general practitioner out-of-hours service. We evaluate whether CRP level has predictive value for diagnosing a child at risk for an SI either at presentation or during followup. The index test was CRP <20 mg/L (rule out an SI) and >80 mg/L (rule in an SI). The reference standard was referral to a pediatric emergency department or diagnosis of an SI. The main outcome measure was CRP value.Results: CRP level was available for 440 children. To rule out an SI, CRP <20 mg/L did not change the probability of having no SI (87.5%). CRP >80 mg/L increased the probability of having an SI from 11.4% (pretest probability) to 21.2% (posttest probability). In children without a diagnosis of SI at presentation, CRP could not predict an SI during follow-up (CRP >80 mg/L: positive likelihood ratio, 2.1, 95% confidence interval, 1.3-3.5; CRP <20 mg/L: negative likelihood ratio, 0.9, 95% confidence interval, 0.7-1.2).Conclusions

Point-of-care C-reactive protein to assist in primary care management of children with suspected non-serious lower respiratory tract infection: a randomised controlled trial

“…CRP levels in this study correspond with reported levels in adults 32 and children with respiratory infections. 27,36 Most children had low CRP levels, as is expected in a primary care setting, because most children suffer from non-serious illnesses. In a recent Norwegian study in children with fever and/or respiratory symptoms presenting to out-of-hours services, antibiotics were prescribed to 13% of children with CRP levels <20 mg/L.…”

Trends in diagnostic tests ordered for children: a retrospective analysis of 2 million laboratory test requests in Oxfordshire, UK from 2005 to 2019

“…CRP is not recommended as routine blood testing in general practice, and its rise in this setting likely represents inappropriate use. 23 In the case of vitamin D testing, NICE guidance only recommends testing in children if they have musculoskeletal symptoms, abnormal serum bone profile or X-Ray findings, suspected bone disease such as osteomalacia or known bone disease such as osteoporosis. 24 A retrospective analysis of vitamin D testing across all age-groups in the Northumbria Healthcare NHS Trust from 2002 to 2017 found a similar rise in testing rates.…”

Typhoid Fever;

“…12 C reactive protein levels in typhoid C-reactive protein (CRP) is an acute-phase protein with increased concentrations in the blood during infections. 13 CRP belongs to the pentraxin family of proteins, because it has five identical subunits, encoded by a single gene on chromosome 1, which associate to form a stable disc-like pentameric structure. 14 Bacterial or inflammatory diseases raise the level of CRP.…”