title: Inappropriate requesting of glycated hemoglobin (Hb A1c) is widespread: assessment of prevalence, impact of national guidance, and practice-to-practice variability.
abstract: BACKGROUND
  Estimates suggest that approximately 25% of requests for pathology tests are unnecessary. Even in diabetes, for which international guidance provides recommended testing frequency, considerable variability in requesting practice exists. Using the diabetes marker, Hb A(1c), we examined (a) the prevalence of under- and overrequesting, (b) the impact of international guidance on prevalence, and (c) practice-to-practice variability.
  
  
  METHODS
  We examined Hb A(1c) requests (519 664 requests from 115 730 patients, January 2001 to March 2011) processed by the Clinical Biochemistry Department, University Hospital of North Staffordshire, and prevalence of requesting outside guidance from intervals between requests was calculated. Requests were classified as "appropriate," "too soon," or "too late." We also assessed the effect of demographic factors and publication of guidance, along with between-practice variability, on prevalence.
  
  
  RESULTS
  Only 49% of requests conformed to guidance; 21% were too soon and 30% were too late. Underrequesting was more common in primary care, in female patients, in younger patients, and in patients with generally poorer control (all P < 0.001); the reverse generally was true for overrequesting. Publication of guidance (e.g., American Diabetes Association, UK National Institute for Health and Clinical Excellence) had no significant impact on under- or overrequesting rates. Prevalence of inappropriate requests varied approximately 6-fold between general practices.
  
  
  CONCLUSIONS
  Although overrequesting was common, underrequesting was more prevalent, potentially affecting longer-term health outcomes. National guidance appears to be an ineffective approach to changing request behavior, supporting the need for a multisystem approach to reducing variability.
authors.affiliation: Department of Clinical Biochemistry, Keele University School of Medicine, University Hospital of North Staffordshire, Stoke-on-Trent, UK.
authors.forename: Owen J
authors.initials: OJ
authors.lastname: Driskell
authors.forename: David
authors.initials: D
authors.lastname: Holland
authors.forename: Fahmy W
authors.initials: FW
authors.lastname: Hanna
authors.forename: Peter W
authors.initials: PW
authors.lastname: Jones
authors.forename: R John
authors.initials: RJ
authors.lastname: Pemberton
authors.forename: Martin
authors.initials: M
authors.lastname: Tran
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Fryer
mesh_terms: D003920:Diabetes Mellitus / Q000175:diagnosis; D005260:Female; D058006:General Practice / Q000592:standards / Q000706:statistics & numerical data*; D006442:Glycated Hemoglobin / Q000032:analysis*; D019983:Guideline Adherence; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians' / Q000592:standards / Q000706:statistics & numerical data*; D011320:Primary Health Care / Q000592:standards / Q000706:statistics & numerical data; D011785:Quality Assurance, Health Care
chemical_list: D006442:Glycated Hemoglobin