title: Validation of hemolysis index thresholds optimizes detection of clinically significant hemolysis.
abstract: OBJECTIVE
  Automated hemolysis index (HI) measurement has standardized the identification and gradation of sample hemolysis.
  
  
  METHODS
  This study evaluates whether clinically significant changes in the concentration of intracellular analytes occur at manufacturer-recommended automated HI thresholds (HI ≥3, >25 mg/dL hemoglobin).
  
  
  RESULTS
  Adult outpatient results for serum potassium (K+), magnesium (Mg), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) were analyzed. Mean ± SD analyte concentration and distribution within the reference interval (RI) were calculated for each HI group (1-7). Potassium results with an HI of 4 or more demonstrated clinically significant differences (≥0.5 mmol/L) in mean K+ concentration and RI classification compared with non-hemolyzed samples (HI = 1). LDH and AST showed clinically significant differences (+20%) for an HI of 3 or more. For Mg, only the group with an HI of 7 demonstrated a clinically significant difference (>25%); however, the number was low.
  
  
  CONCLUSIONS
  Mean measured potassium concentrations are not clinically significantly affected by hemolysis at the manufacturer-recommended HI threshold, while AST and LDH are. Aligning reporting of sample hemolysis with clinically significant changes provides clinically meaningful alerts regarding this common pre-analytic error.
authors.affiliation: From the Department of Pathology, University Hospitals Case Medical Center, Cleveland, OH, and.
authors.forename: Tanu
authors.initials: T
authors.lastname: Goyal
authors.affiliation: From the Department of Pathology, University Hospitals Case Medical Center, Cleveland, OH, and Case Western Reserve University, Cleveland, OH. Christine.Schmotzer@UHhospitals.org.
authors.forename: Christine L
authors.initials: CL
authors.lastname: Schmotzer
mesh_terms: D000328:Adult; D001219:Aspartate Aminotransferases / Q000097:blood; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000592:standards*; D006454:Hemoglobins / Q000032:analysis; D006461:Hemolysis; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008274:Magnesium / Q000097:blood; D011188:Potassium / Q000097:blood; D012016:Reference Values
chemical_list: D006454:Hemoglobins; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D008274:Magnesium; D011188:Potassium
keywords: Automated chemistry; Hemolysis; Preanalytic error; Specimen integrity