Adjustment of lactate dehydrogenase concentration results according to the haemolysis index following in vitro haemolysis.

In the presence of haemolysis, the interpretation of the Lactate dehydrogenase (LDH) activity result is a major operational challenge for medical laboratories: if the origin is intravascular, then the measurement will reflect the clinical reality, but in extravascular haemolysis, the laboratory will be confronted with an artefactual increase leading to false-positive high results. The aim of our study was to evaluate the adjustment of LDH concentration results according to the haemolysis index (HI). After designed a mathematical model to correct the LDH measured as a function of the haemolysis index using a Cobas 8000 analyser (Roche diagnostics, Mannheim, Germany), LDH measurement of seventy-four duplicate samples were tested before and after exposure to extravascular haemolysis process. After haemolysis process, a significant increase haemolysis index (Man-Whitney U-Test  < 0.0001) were observed. Before process the HI median was 4 [2.0 - 6.75] and after HI median was 18 [10 - 35.75]. Without correction, LDH results showed a significant increase ( < 0.001) after haemolysis process and substantial analytical discrepancies (31/74) were observed according to TEa of CLIA. After correction, data showed no significant difference ( = 0.497) and the mathematical algorithm allowed to reduce the analytical discrepancies (2/74). If haemolysis was present , the mathematical algorithm increased the accuracy of the LDH results. However, the lack of discrimination between and haemolysis requires caution and the results should be reported only as a commentary to inform the clinician.