title: C-Reactive Protein Level as Diagnostic Marker in Young Febrile Children Presenting in a General Practice Out-of-Hours Service.
abstract: It is unclear how well a C-reactive protein (CRP) value predicts a serious infection (SI) in young febrile children in general practice.
  
  
  
  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 follow-up. 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.
  
  
  
  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).
  
  
  
  In general practice CRP has little clinically relevant value in discriminating febrile children in need of medical care from those who are not.
authors.affiliation: From the Department of General Practice, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands (MK, GE, BWK, AMB, MYB); and the Department of General Practice, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands (MYB).
authors.forename: Marijke
authors.initials: M
authors.lastname: Kool
authors.affiliation: From the Department of General Practice, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands (MK, GE, BWK, AMB, MYB); and the Department of General Practice, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands (MYB).
authors.forename: Gijs
authors.initials: G
authors.lastname: Elshout
authors.affiliation: From the Department of General Practice, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands (MK, GE, BWK, AMB, MYB); and the Department of General Practice, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands (MYB).
authors.forename: Bart W
authors.initials: BW
authors.lastname: Koes
authors.affiliation: From the Department of General Practice, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands (MK, GE, BWK, AMB, MYB); and the Department of General Practice, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands (MYB).
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Bohnen
authors.affiliation: From the Department of General Practice, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands (MK, GE, BWK, AMB, MYB); and the Department of General Practice, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands (MYB). m.y.berger@umcg.nl.
authors.forename: Marjolein Y
authors.initials: MY
authors.lastname: Berger
mesh_terms: D039602:After-Hours Care / Q000379:methods*; D002097:C-Reactive Protein / Q000032:analysis*; D002675:Child, Preschool; D004636:Emergency Service, Hospital; D005260:Female; D005334:Fever / Q000097:blood* / Q000175:diagnosis; D058006:General Practice / Q000379:methods*; D006801:Humans; D007223:Infant; D007239:Infections / Q000097:blood* / Q000175:diagnosis; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012017:Referral and Consultation
chemical_list: D002097:C-Reactive Protein
keywords: C-Reactive Protein; Child; Cohort Studies; Family Practice; Fever; Follow-Up Studies; General Practice; General Practitioners; Hospital Emergency Service; Hospital Records; Humans; Outcome Assessment (Health Care); Point-of-Care Systems; Probability; Prospective Studies; Referral and Consultation