Interference of lipemia in samples for routine coagulation testing using a Sysmex CS-5100 coagulometer.

Area of Science:

• Clinical Chemistry
• Hematology
• Laboratory Medicine

Background:

• Lipemia in patient samples can lead to analytical errors in photometric coagulation assays.
• In vitro studies using spiked lipids do not accurately reflect real-world lipemic interferences.
• Natively lipemic samples present a more accurate model for interference assessment.

Purpose of the Study:

• To evaluate the necessity and clinical relevance of high-speed centrifugation for reducing lipemic interference in coagulation tests.
• To determine if retesting lipemic samples after centrifugation is justified based on analytical and clinical significance.
• To compare results before and after centrifugation using Bland-Altman analysis and quality specifications.

Main Methods:

• Analysis of 101 lipemic samples using a Sysmex CS-5100 coagulometer.
• Measurement of PT, aPTT, fibrinogen (Clauss assay), antithrombin activity, and D-dimer concentration.
• Comparison of results before and after double high-speed centrifugation, employing Bland-Altman tests and quality specifications for imprecision.

Main Results:

• Statistically significant differences were observed for PT, antithrombin activity, and fibrinogen.
• Fibrinogen results showed significant differences only for samples with concentrations >2 g/L.
• The mean percentual difference for PT and antithrombin activity was below biologic variation and quality specifications.

Conclusions:

• High-speed centrifugation is generally unnecessary for PT, aPTT, D-dimer, and antithrombin activity if initial results are obtainable.
• Centrifugation is necessary for fibrinogen testing when levels exceed 2 g/L or if initial results cannot be determined.
• Observed differences for PT and antithrombin activity are considered 'noise' and lack analytical or clinical relevance.