PB1074 - Influence of hemolysis, icterus and lipemia on Owren PT measured with a viscosity based detection coagulometer

Background: The presence of hemolysis (H), icterus (I) or lipemia (L) is reported to be a major cause of pre-analytical errors [Salvagno GL et al., J Eval Clin Pract 2008]. It has been shown that H, I, L do not affect routine coagulation assays in a viscosity based detection coagulometer [Wolley A et al., Int J Lab Hem 2016]. However, only Quick PT assay was studied in this routine panel.

Aims: Evaluate the impact of H, I and L on Owren PT measured through mechanical clot detection.

Methods: Four different pools were prepared from non-hemolyzed citrated blood samples. Each pool was divided into 4 parts, to induce different levels of hemolysis: no hemolysis (H0) and spurious hemolysis by 1, 3 or 5 aspirations through a thin needle (H1, H3, H5 respectively). Lipemic samples were created by adding Lipofundin S 20% (B.Braun SpA, Italy) in 4 different plasma pools at 0, 200, 500 and 1000 mg/dL respectively. Similarly, icteric samples were made by adding bilirubin (Sigma-Aldrich, MO, USA) to 4 different plasma pools at concentrations of 0, 5, 20 and 40 mg/dL.
All pools were different for H, I and L experiments. Hemoglobin, bilirubin and triglycerides levels of all samples were checked and samples were then analyzed using STA-SPA+ on STA R Max analyzer (Diagnostica Stago, France).

Results: Results obtained are detailed in table 1.
Maximal observed deviation induced by H, I or L was a change of 0.07 on INR (from 1.44 to 1.51) for hemolysis, 0.08 on INR (from 1.70 to 1.78) for lipemia and 0.14 on INR (from 1.47 to 1,33). None of these differences proved to be clinically significant.

Conclusion(s): Consistent with the published observation on Quick PT, hemolysis, icterus and lipemia do not interfere with Owren PT results as measured with STA-SPA+ reagent on STA R Max analyzer.