title: Diagnostic disagreement between tests of evacuatory function: a prospective study of 100 constipated patients.
abstract: BACKGROUND
  Evacuatory dysfunction (ED) is a common cause of constipation and may be sub-classified on the basis of specialist tests. Such tests may guide treatment e.g., biofeedback therapy for 'functional' defecatory disorders (FDD). However, there is no gold standard, and prior studies have not prospectively and systematically compared all tests that are used to diagnose forms of ED.
  
  
  METHODS
  One hundred consecutive patients fulfilling Rome III criteria for functional constipation underwent four tests: expulsion of a rectal balloon distended to 50 mL (BE50 ) or until patients experienced the desire to defecate (BEDDV ), evacuation proctography (EP) and anorectal manometry. Yields and agreements between tests for the diagnosis of ED and FDD were assessed.
  
  
  RESULTS
  Positive diagnostic yields for ED were: BEDDV 18%, BE50 31%, EP 38% and anorectal manometry (ARM) 68%. Agreement was substantial between the two balloon tests (k = 0.66), only fair between proctography and BE50 (k = 0.27), poor between manometry and proctography (k = 0.01), and there was no agreement between the balloon tests and manometry (k = -0.07 for both BE50 and BEDDV ). For the diagnosis of FDD, there was only fair agreement between ARM and EP (k = 0.23), ARM ± BE50 and EP (k = 0.18), ARM and EP ± BE50 (k = 0.30) and ARM ± BE50 and EP ± BE50 (k = 0.23).
  
  
  CONCLUSIONS
  There is considerable disagreement between the results of various tests used to diagnose ED and FDD. This highlights the need for a reappraisal of both diagnostic criteria, and what represents the 'gold standard' investigation.
authors.affiliation: National Centre for Bowel Research and Surgical Innovation (NCBRSI) and GI Physiology Unit (GIPU), Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Palit
authors.affiliation: National Centre for Bowel Research and Surgical Innovation (NCBRSI) and GI Physiology Unit (GIPU), Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Thin
authors.affiliation: National Centre for Bowel Research and Surgical Innovation (NCBRSI) and GI Physiology Unit (GIPU), Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: C H
authors.initials: CH
authors.lastname: Knowles
authors.affiliation: National Centre for Bowel Research and Surgical Innovation (NCBRSI) and GI Physiology Unit (GIPU), Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Lunniss
authors.affiliation: Division of Gastroenterology and Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research Program, Mayo Clinic and Mayo Foundation, Rochester, MN, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Bharucha
authors.affiliation: National Centre for Bowel Research and Surgical Innovation (NCBRSI) and GI Physiology Unit (GIPU), Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK. s.palit@qmul.ac.uk.
authors.forename: S M
authors.initials: SM
authors.lastname: Scott
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003248:Constipation / Q000175:diagnosis* / Q000503:physiopathology*; D003672:Defecation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D011446:Prospective Studies; D055815:Young Adult
keywords: anorectal manometry; balloon expulsion test; chronic constipation; proctography