title: What is the acceptable hemolysis index for the measurements of plasma potassium, LDH and AST?
abstract: Hemolysis is a cause of variability in test results for plasma potassium, LDH and AST and is a non-negligible part of measurement uncertainty. However, allowable levels of hemolysis provided by reagent suppliers take neither analytical variability (trueness and precision) nor the measurand into account. Using a calibration range of hemolysis, we measured the plasma concentrations of potassium, LDH and AST, and hemolysis indices with a Cobas C501 analyzer (Roche Diagnostics(®), Meylan, France). Based on the allowable total error (according to Ricós et al.) and the expanded measurement uncertainty equation we calculated the maximum allowable bias for two concentrations of each measurand. Finally, we determined the allowable hemolysis indices for all three measurands. We observed a linear relationship between the observed increases of concentration and hemolysis indices. The LDH measurement was the most sensitive to hemolysis, followed by AST and potassium measurements. The determination of the allowable hemolysis index depends on the targeted measurand, its concentration and the chosen level of requirement of allowable total error.
authors.affiliation: Laboratoire de biologie, Saint-Joseph-Saint-Luc, Lyon, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Rousseau
authors.affiliation: Laboratoire de biologie, Saint-Joseph-Saint-Luc, Lyon, France.
authors.forename: Raphaëlle
authors.initials: R
authors.lastname: Pige
authors.affiliation: Laboratoire de biochimie et biologie moléculaire, Groupement hospitalier Edouard Herriot, Lyon, France.
authors.forename: Richard
authors.initials: R
authors.lastname: Cohen
authors.affiliation: Laboratoire de biologie, Saint-Joseph-Saint-Luc, Lyon, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Pecquet
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000097:blood*; D001774:Blood Chemical Analysis / Q000379:methods / Q000592:standards; D002138:Calibration; D004796:Clinical Enzyme Tests / Q000592:standards; D006305:Health Status Indicators; D006461:Hemolysis / Q000502:physiology*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood* / Q000378:metabolism; D011188:Potassium / Q000097:blood*; D012016:Reference Values
chemical_list: C113037:ABCB7 protein, human; D018528:ATP-Binding Cassette Transporters; D007770:L-Lactate Dehydrogenase; D011188:Potassium
keywords: AST; LDH; bias; hemolysis; potassium; uncertainty