title: Electronic health records and the frequency of diagnostic test orders.
abstract: OBJECTIVE
  To determine whether electronic health record (EHR) access influences the number of laboratory and imaging tests ordered, which is a frequently cited mechanism for EHR-enabled cost savings.
  
  
  METHODS
  We analyzed data on non-federally employed office-based physicians from the 2008 to 2012 Electronic Health Medical Records Survey, a supplement to the National Ambulatory Medical Care Survey.
  
  
  METHODS
  We estimated logistic regressions to determine the relationship between EHR utilization and the volume of laboratory and imaging tests ordered in our study population, controlling for age, sex, race, clinic type, payer type, health status, comorbidities, and new patients.
  
  
  RESULTS
  Physicians who actively used an EHR system ordered more complete blood count (CBC) tests than physicians who did not (odds ratio [OR], 1.34; P <.001), even after adjusting for patient demographics, health status, and case mix. EHR-using physicians also ordered more computerized tomography scans (OR, 1.41; P <.001) and x-rays (OR, 1.39; P <.001); the difference for magnetic resonance imaging scans was not significant (OR, 1.08; P = .449). Subgroup analysis highlighted differences in ordering among various patient cohorts.
  
  
  CONCLUSIONS
  Using the most recent available nationally representative data, excluding federal and Veterans Affairs' hospitals, we found that physicians with EHR access ordered more tests than their non-EHR counterparts, thus contradicting a common rationale for EHR implementation. We argue that EHR use may actually increase healthcare expenditures by facilitating the ease of ordering tests. Whether these extra tests carry clinical utility requires further analysis.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Hakim
authors.affiliation: Stanford School of Medicine, Stanford Graduate School of Business, 291 Campus Dr, Stanford, CA 94305. E-mail: shathi@stanford.edu.
authors.forename: Sejal
authors.initials: S
authors.lastname: Hathi
authors.forename: Archana
authors.initials: A
authors.lastname: Nair
authors.forename: Trishna
authors.initials: T
authors.lastname: Narula
authors.forename: Jay
authors.initials: J
authors.lastname: Bhattacharya
mesh_terms: D001774:Blood Chemical Analysis; D016208:Databases, Factual; D003952:Diagnostic Imaging / Q000706:statistics & numerical data*; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data*; D057286:Electronic Health Records / Q000706:statistics & numerical data*; D005260:Female; D018166:Health Care Reform; D019538:Health Care Surveys; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008297:Male; D015999:Multivariate Analysis; D010818:Practice Patterns, Physicians'; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data; D014481:United States