Electrical impedance measurement as an endpoint detection method for routine coagulation tests.

Area of Science:

• Clinical Chemistry
• Hematology
• Biomedical Engineering

Background:

• Prothrombin time (PT) is a critical measure of blood coagulation.
• Traditional PT measurement relies on absorbance-based methods.
• Adapting existing laboratory equipment for novel diagnostic applications is valuable.

Purpose of the Study:

• To adapt a whole-blood platelet aggregometer for measuring electrical impedance changes during PT estimations.
• To compare the impedance-based PT method with the conventional absorbance method.
• To assess the correlation between impedance signal amplitude and plasma fibrinogen concentration.

Main Methods:

• Utilized a whole-blood platelet aggregometer to monitor electrical impedance changes in plasma.
• Analyzed the impedance curve for an acceleration phase indicative of coagulation onset.
• Correlated the amplitude of impedance change with plasma fibrinogen levels.
• Performed statistical analysis comparing PT values derived from impedance and absorbance methods.

Main Results:

• The impedance curve exhibited an acceleration phase analogous to absorbance-based coagulation.
• A significant correlation was observed between impedance signal amplitude and plasma fibrinogen concentration.
• While statistically different, PT values from impedance and absorbance methods showed good correlation.
• The impedance method demonstrated reproducibility but was noted as laborious.

Conclusions:

• Electrical impedance measurement using an adapted platelet aggregometer is a viable method for PT estimation.
• The method shows potential for assessing fibrinogen concentration.
• Further optimization with more sensitive instrumentation and improved electrode design is recommended.
• Reagent system modifications may enhance the impedance-based coagulation assay.