Automated antithrombin III assay with a centrifugal analyser

Area of Science:

• Biochemistry
• Hematology
• Clinical Chemistry

Background:

• Antithrombin III is a crucial inhibitor of coagulation factors.
• Accurate measurement of antithrombin III function is vital for clinical diagnostics.
• Existing assays for antithrombin III activity can be time-consuming or lack precision.

Purpose of the Study:

• To develop and validate an automated amidolytic assay for measuring the factor Xa inactivating function of antithrombin III.
• To assess the precision and correlation of the new assay with established methods.

Main Methods:

• An automated amidolytic assay using a centrifugal analyzer was developed.
• Plasma was incubated with excess factor Xa in the presence of heparin.
• Residual factor Xa was quantified using a chromogenic substrate (Bz-Ile-Glu-Gly-Arg-pNA).

Main Results:

• The automated assay demonstrated favorable precision compared to clotting assays and immunoassay.
• A strong correlation (r = 0.82) was observed between the automated assay and antithrombin III immunoassay results.
• Heparin was shown to accelerate antithrombin III saturation with factor Xa.

Conclusions:

• The developed automated amidolytic assay provides a precise and reliable method for measuring antithrombin III's factor Xa inactivating function.
• This automated assay offers a valuable alternative for clinical laboratories, correlating well with existing methods.