title: Estimation of biomarker distributions using laboratory data collected during routine delivery of medical care.
abstract: OBJECTIVE
  To examine the extent to which commonly ordered laboratory values obtained from large health care databases are representative of the distribution of laboratory values from the general population as reflected in the National Health and Nutrition Examination Survey.
  
  
  METHODS
  Means of test values from commercial insurance laboratory data and National Health and Nutrition Examination Survey data were compared. Inverse probability of selection weighting was used to account for possible selection bias and to create comparability between the two data sources.
  
  
  RESULTS
  The average values of most of the laboratory results from routine care were very close to their population means as estimated from NHANES. Tests that were more selectively ordered tended to differ. The inverse probability of selection weighting approach generally had a small effect on the estimated means but did improve estimation of some of the more selected tests.
  
  
  CONCLUSIONS
  Commonly ordered laboratory tests appear to be representative of values from the underlying population. This suggests that trends and other patterns in biomarker levels in the population may be reasonably studied using data collected during the routine delivery of medical care.
authors.affiliation: Department of Epidemiology, UNC Gillings School of Global Public Health, UNC Chapel Hill, Chapel Hill, NC; Cecil G. Sheps Center for Health Services Research, University of North Carolina, Chapel Hill. Electronic address: abrookhart@unc.edu.
authors.forename: Maurice Alan
authors.initials: MA
authors.lastname: Brookhart
authors.affiliation: Department of Epidemiology, UNC Gillings School of Global Public Health, UNC Chapel Hill, Chapel Hill, NC.
authors.forename: Jonathan V
authors.initials: JV
authors.lastname: Todd
authors.affiliation: Department of Epidemiology, UNC Gillings School of Global Public Health, UNC Chapel Hill, Chapel Hill, NC.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
authors.affiliation: Cecil G. Sheps Center for Health Services Research, University of North Carolina, Chapel Hill.
authors.forename: B Diane
authors.initials: BD
authors.lastname: Reams
authors.affiliation: Department of Epidemiology, UNC Gillings School of Global Public Health, UNC Chapel Hill, Chapel Hill, NC.
authors.forename: Virginia
authors.initials: V
authors.lastname: Pate
authors.affiliation: UNC School of Medicine, University of North Carolina Kidney Center, Chapel Hill.
authors.forename: Abhijit V
authors.initials: AV
authors.lastname: Kshirsagar
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis*; D016208:Databases, Factual / Q000706:statistics & numerical data; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data*; D015340:Epidemiologic Research Design; D006801:Humans; D007345:Insurance Claim Review; D008875:Middle Aged; D009749:Nutrition Surveys / Q000706:statistics & numerical data*; D011336:Probability; D012189:Retrospective Studies; D015983:Selection Bias
chemical_list: D015415:Biomarkers
keywords: Epidemiologic methods; Laboratories; National Health and Nutrition Examination Survey; Selection bias