title: Assessing the Impact of Analytical Error on Perceived Disease Severity.
abstract: BACKGROUND
  The perception of the severity of disease from laboratory results assumes that the results are free of analytical error; however, analytical error creates a spread of results into a band and thus a range of perceived disease severity.
  
  
  OBJECTIVE
  To assess the impact of analytical errors by calculating the change in perceived disease severity, represented by the hazard ratio, using non-high-density lipoprotein (nonHDL) cholesterol as an example.
  
  
  METHODS
  We transformed nonHDL values into ranges using the assumed total allowable errors for total cholesterol (9%) and high-density lipoprotein cholesterol (13%). Using a previously determined relationship between the hazard ratio and nonHDL, we calculated a range of hazard ratios for specified nonHDL concentrations affected by analytical error.
  
  
  RESULTS
  Analytical error, within allowable limits, created a band of values of nonHDL, with a width spanning 30 to 70 mg/dL (0.78-1.81 mmol/L), depending on the cholesterol and high-density lipoprotein cholesterol concentrations. Hazard ratios ranged from 1.0 to 2.9, a 16% to 50% error. Increased bias widens this range and decreased bias narrows it.
  
  
  CONCLUSIONS
  Error-transformed results produce a spread of values that straddle the various cutoffs for nonHDL. The range of the hazard ratio obscures the meaning of results, because the spread of ratios at different cutoffs overlap. The magnitude of the perceived hazard ratio error exceeds that for the allowable analytical error, and significantly impacts the perceived cardiovascular disease risk. Evaluating the error in the perceived severity (eg, hazard ratio) provides a new way to assess the impact of analytical error.
authors.affiliation: From Quest Diagnostics, Madison, New Jersey. All authors are employees of Quest Diagnostics, Madison, New Jersey.
authors.forename: Martin H
authors.initials: MH
authors.lastname: Kroll
authors.forename: Carl C
authors.initials: CC
authors.lastname: Garber
authors.forename: Caixia
authors.initials: C
authors.lastname: Bi
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Suffin
mesh_terms: D008076:Cholesterol, HDL / Q000097:blood*; D003955:Diagnostic Tests, Routine / Q000379:methods / Q000592:standards*; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood*; D015203:Reproducibility of Results; D012720:Severity of Illness Index
chemical_list: D008076:Cholesterol, HDL; D008075:Lipoproteins, HDL