title: Excessive diagnostic testing in acute kidney injury.
abstract: BACKGROUND
  The patterns, performance characteristics, and yield of diagnostic tests ordered for the evaluation of acute kidney injury (AKI) have not been rigorously evaluated.
  
  
  METHODS
  We characterized the frequency of AKI diagnostic testing for urine, blood, radiology, and pathology tests in all adult inpatients who were admitted with or developed AKI (N = 4903 patients with 5731 AKI episodes) during a single calendar year. We assessed the frequency of abnormal test results overall and by AKI stage. We manually reviewed electronic medical records to evaluate the diagnostic yield of selected urine, blood, and radiology tests. Diagnostic yield of urine and blood tests was determined based on whether an abnormal test affected AKI diagnosis or management, whereas diagnostic yield of radiology tests was based on whether an abnormal test resulted in a procedural intervention. In sensitivity analyses we also evaluated appropriateness of testing using prespecified criteria.
  
  
  RESULTS
  Frequency of testing increased with higher AKI stage for nearly all diagnostic tests, whereas frequency of detecting an abnormal result increased for some, but not all, tests. Frequency of detecting an abnormal result was highly variable across tests, ranging from 0 % for anti-glomerular basement membrane testing to 71 % for urine protein testing. Many of the tests evaluated had low diagnostic yield. In particular, selected urine and blood tests were unlikely to impact AKI diagnosis or management, whereas radiology tests had greater clinical utility.
  
  
  CONCLUSIONS
  In patients with AKI, many of the diagnostic tests performed, even when positive or abnormal, may have limited clinical utility.
authors.affiliation: Division of Renal Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. deleaf@partners.org.
authors.forename: David E
authors.initials: DE
authors.lastname: Leaf
authors.affiliation: Division of Renal Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. asrivastava2@partners.org.
authors.forename: Anand
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: Division of Renal Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. xiaoxizeng@hotmail.com.
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Division of Renal Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. gmmcmahon@partners.org.
authors.forename: Gearoid M
authors.initials: GM
authors.lastname: McMahon
authors.affiliation: Division of Renal Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. hecroy@gmail.com.
authors.forename: Heather E
authors.initials: HE
authors.lastname: Croy
authors.affiliation: Division of Renal Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. mmendu@partners.org.
authors.forename: Mallika L
authors.initials: ML
authors.lastname: Mendu
authors.affiliation: Department of Health Policy and Management, Harvard School of Public Health, Boston, MA, 02115, USA. akachalia@partners.org.
authors.forename: Allen
authors.initials: A
authors.lastname: Kachalia
authors.affiliation: Division of Renal Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. swaikar@partners.org.
authors.forename: Sushrut S
authors.initials: SS
authors.lastname: Waikar
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000175:diagnosis* / Q000652:urine; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood; D001323:Autoantibodies / Q000097:blood; D001706:Biopsy / Q000706:statistics & numerical data; D001797:Blood Protein Electrophoresis / Q000706:statistics & numerical data; D002452:Cell Count / Q000706:statistics & numerical data; D003176:Complement C3 / Q000378:metabolism; D003181:Complement C4 / Q000378:metabolism; D003404:Creatinine / Q000097:blood / Q000652:urine; D003450:Cryoglobulins / Q000378:metabolism; D004804:Eosinophils; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000652:urine; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012964:Sodium / Q000652:urine; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data; D014463:Ultrasonography / Q000706:statistics & numerical data; D019564:Unnecessary Procedures / Q000706:statistics & numerical data*; D014508:Urea / Q000652:urine; D016482:Urinalysis / Q000706:statistics & numerical data; D014556:Urine / Q000166:cytology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D003176:Complement C3; D003181:Complement C4; D003450:Cryoglobulins; C051951:antiglomerular basement membrane antibody; D014508:Urea; D012964:Sodium; D003404:Creatinine