[Hemolysis interferences on frequently required stat analysis: a French multicentric study]

Hemolysis should lead to changes in test results. Our study evaluated the impact of hemolysis on 26 blood measurements of stat biochemistry markers (sodium, potassium, chloride, urea, creatinine, glucose, total protein, calcium, magnesium, inorganic phosphorus, uric acid, C-reactive protein, total bilirubin, ASAT, ALAT, LDH, creatine kinase, alkaline phosphatase, γ glutamyl-transferase, lipase, alcohol, iron, β hCG, troponins, natriuretic peptides) determined with 13 different types of instruments in 17 hospital laboratories. Four pools of samples (collected from lithium heparin or EDTA or sodium fluoride tubes, according to the measured parameters) were overloaded with five increasing concentrations of whole blood lysate (final concentration from 0 to 2.000 mg/dL). Replication was performed for each assay, average values were calculated and differences between results with and without lysate were analyzed. A difference exceeding the square root of the sum of both squared analytic and biologic imprecisions for each analyte, was judged to be significant. Except homogeneous and expected impact of hemolysis on certain parameters like potassium, LDH... (due to their intra-erythrocyte concentration) a heterogeneous effect was found for other parameters, according to the analyzer and/or to the methodology. In summary, this study confirms the importance of mastering the measurement of the hemolysis and leads to several recommendations: (i) biologists should have a good knowledge of the impact of hemolysis on the measurements they perform, depending on their chosen analyzers; (ii) if an interference is noticed, it is recommended to add to the result a relevant comment and to check that the comment is properly edited in the laboratory computer software and appears on printed and transmitted results.