title: Sensitivity and specificity of C-reactive protein and α(1) -acid glycoprotein for episodes of acute infection among children in Kilimanjaro, Tanzania.
abstract: OBJECTIVE
  Biomarkers of inflammation, including C-reactive protein (CRP) and α(1) -acid glycoprotein (AGP), have tremendous potential in anthropological, public health, and nutrition research as objective indicators of acute infection; however, their usage is limited by the lack of widely agreed upon, reliable cutpoints to define infection. We assessed the sensitivity and specificity of CRP and AGP for identifying acute infectious disease (ID) episodes among children in the Kilimanjaro region of Tanzania.
  
  
  METHODS
  Data were available from 43 3- to 5-year-old children. CRP and AGP were measured in capillary whole dried blood spots (DBS). Two-week morbidity history interviews with children's primary caregivers were used to detect recent episodes of acute ID. Specimens and morbidity history interviews were collected from each child on one (n = 13) or two (n = 30) occasions for 73 paired interviews and specimens.
  
  
  RESULTS
  We evaluated CRP and AGP for identifying acute infection (report of fever, diarrhea, or vomiting in the last week): CRP ≥ 1.1 mg/l had sensitivity of 57.14% and specificity of 86.44%; AGP ≥ 0.76 g/l had sensitivity of 57.14% and specificity of 72.41%. The combined definition (AGP ≥ 0.76 g/l or CRP ≥ 1.1 mg/l) had sensitivity of 71.43% and specificity of 70.69%.
  
  
  CONCLUSIONS
  Among children in Kilimanjaro, Tanzania, assessed in whole blood stored as DBS, AGP ≥ 0.76 g/l or CRP ≥ 1.1 mg/l provided the best definition of acute infection. Whether this definition is appropriate for use in other populations remains to be determined.
authors.affiliation: Department of Anthropology, University of Washington, Seattle, WA 98195, USA. kwander@u.washington.edu
authors.forename: Katherine
authors.initials: K
authors.lastname: Wander
authors.forename: Eleanor
authors.initials: E
authors.lastname: Brindle
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: O'connor
mesh_terms: D000208:Acute Disease; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D002675:Child, Preschool; D003141:Communicable Diseases / Q000175:diagnosis* / Q000453:epidemiology; D003967:Diarrhea / Q000175:diagnosis / Q000453:epidemiology; D059788:Dried Blood Spot Testing / Q000379:methods; D005260:Female; D005334:Fever / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D007249:Inflammation / Q000175:diagnosis / Q000453:epidemiology; D008297:Male; D008403:Mass Screening / Q000379:methods*; D009961:Orosomucoid / Q000032:analysis*; D012680:Sensitivity and Specificity; D013636:Tanzania / Q000453:epidemiology; D014839:Vomiting / Q000175:diagnosis / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D009961:Orosomucoid; D002097:C-Reactive Protein