title: The diagnostic yield of intravenous urography.
abstract: BACKGROUND
  Intravenous urography (IVU) is considered an integral imaging component of the nephro-urological work-up in a wide array of clinical settings. At our institution there is an open-access policy with regard to requesting IVU studies.
  
  
  METHODS
  In a prospective, blinded observational study we undertook to assess the diagnostic yield of IVU with respect to the source of referral (i.e. Urology, Nephrology, GP, A & E, other speciality) and the presenting features, such as renal colic, haematuria, bladder outflow obstruction, recurrent urinary tract infection (UTI) etc. Two hundred consecutive patients were evaluated.
  
  
  RESULTS
  Overall, 23% of tests were positive. There was a highly significant difference in diagnostic yield between the groups (P<0.001 for both referral source and test indication). A positive result was most likely after referral by a kidney specialist (37.1%) and when the test indication was renal colic (42%) or haematuria (32%). The yield was <15% in all other circumstances, with 94.9% and 92.1% of GP- and other hospital speciality-initiated IVUs being negative. When investigating recurrent UTI, 91.7% of tests were negative and 86.2% were negative when the indication was bladder outflow obstruction.
  
  
  CONCLUSIONS
  It is suggested that an open access policy for IVU is not justified, especially when cost and the risk associated with contrast media and radiation exposure are taken into account. Our study supports the abandonment of routine IVU in the investigation of UTI and bladder outflow obstruction.
authors.affiliation: Departments of Nephrology and Diagnostic Radiology, Beaumont Hospital, Dublin, Ireland.
authors.forename: M A
authors.initials: MA
authors.lastname: Little
authors.forename: D B
authors.initials: DB
authors.lastname: Stafford Johnson
authors.forename: J P
authors.initials: JP
authors.lastname: O'Callaghan
authors.forename: J J
authors.initials: JJ
authors.lastname: Walshe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004635:Emergency Medicine; D005194:Family Practice; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009398:Nephrology; D011446:Prospective Studies; D012017:Referral and Consultation; D016037:Single-Blind Method; D001748:Urinary Bladder Neck Obstruction / Q000000981:diagnostic imaging; D014552:Urinary Tract Infections / Q000000981:diagnostic imaging; D014567:Urography / Q000592:standards*; D014570:Urologic Diseases / Q000000981:diagnostic imaging*; D014572:Urology