title: Performance of blood tests in diagnosis of inflammatory bowel disease in a specialist clinic.
abstract: OBJECTIVE
  To determine the reliability of a panel of blood tests in screening for ulcerative colitis and Crohn's disease.
  
  
  METHODS
  The subjects were 153 children referred to a paediatric gastroenterology department with possible inflammatory bowel disease (IBD). Of these, 103 were found to have IBD (Crohn's disease 60, ulcerative colitis 37, indeterminate colitis 6). The 50 without IBD formed the controls. Blood tests evaluated included haemoglobin, platelet count, ESR, CRP, and albumin. Receiver operating characteristic curves were used where possible to determine optimal threshold values. Binary logistic regression analysis was used to investigate the five screening tests in combination, and a stepwise method was used to find the best test combination.
  
  
  RESULTS
  The optimal screening strategy used a combination of haemoglobin and platelet count and "1 of 2 abnormal" as the criterion for positivity. This was associated with a sensitivity of 90.8% (95% CI 83.3 to 95.7%), a specificity of 80.0% (95% CI 65.7 to 89.8%), and positive and negative predictive values of 94.4% and 75.9% respectively.
  
  
  CONCLUSIONS
  Haemoglobin and platelet count provide a useful screening test combination for patients with suspected IBD. These tests are not completely reliable however. If clinical suspicion is high further investigations are required.
authors.affiliation: Department of Clinical Chemistry, Birmingham Children's Hospital, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Cabrera-Abreu
authors.forename: P
authors.initials: P
authors.lastname: Davies
authors.forename: Z
authors.initials: Z
authors.lastname: Matek
authors.forename: M S
authors.initials: MS
authors.lastname: Murphy
mesh_terms: D000293:Adolescent; D000553:Ambulatory Care / Q000592:standards; D000554:Ambulatory Care Facilities; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003093:Colitis, Ulcerative / Q000175:diagnosis*; D003424:Crohn Disease / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis
chemical_list: D015415:Biomarkers; D012709:Serum Albumin; D002097:C-Reactive Protein