DiaPharma Group, Inc.

Not Yet Available

Reagent kit for the determination of blood coagulation factor XIII (FXIII) acivity to detect inherited or acquired FXIII deficiencies, abnormal FXIII with decreased activity and elevated FXIII level.

Summary

Inherited FXIII deficiency is a rare, but severe bleeding diathesis with occasional would healing impairment and in women with habitual abortion. Acquired FXIII deficiency due to an anti-FXIII autoantibody is also a very severe haemorrhagic diathesis. Consumption of FXIII in various diseases (malignant diseases, Chron disease, Henoch-Schönlein purpura, major surgery, etc.) usually results in moderate decrease of FXIII level. The assay can also be used for monitoring FXIII replacement therapy.

Method

FXIII is transformed into an active transglutaminase (active FXIII; FXIIIa) during its activation. The determination of FXIII activity is based on the measurement of ammonia released during the transglutaminase reaction. The original spectrophotometric, kinetic, enzymatic assay1 was modified and optimized2. FXIII present in the plasma sample is activated by thrombin and Ca2+. Fibrin formed from fibrinogen by thrombin accelerates this reaction. The polymerisation of fibrin is prevented by a tetrapeptide. The formed FXIIIa then cross-links the amine substrate glycine ethyl ester (GEE) to the glutamine residue of specific peptide substrate PI(1-12), and ammonia is released. In the indicator reaction the amount of released ammonia is monitored in a glutamate dehydrogenase catalysed NADPHdependent reaction. The consumption of NADPH is measured spectrophotometrically by the decrease of absorbance at 340 nm. Within a time window the decrease of absorbance is directly proportional to the FXIII activity.

Reagents

1. Activator reagent (lyophilized, 3 vials)
2. Detection reagent (lyophilized, 3 vials)
3. NADPH reagent (lyophilized, 3 vials)
4. Inhibitor reagent (lyophilized, 3 vials)
5. Stabilizer solution (5.8 g/l Na-azide, 1 vial, 6 ml)