DiaPharma Group, Inc.

Reagent kit for carrying out Factor VIII inhibitor assays. For Research use only.

COMPOSITION & REAGENT PREPARATION

The Factor VIII Inhibitor Reagent kit for 2-4 determinations contains:

• 2 vials x Factor VIII Normal Plasma ~ 3 mL.
  Factor VIII Normal Plasma, 2 vials, to be dissolved with the amount of distilled water indicated on the label. The normal plasma then contains one I.U. Factor VIII/mL.
• 1 vial x Factor VIII Inhibitor Plasma 1 mL.
  Factor VIII Inhibitor Plasma, to be dissolved in 1 mL distilled water. The number of Factor VIII inhibitor units/mL (Bethesda units) is given on the label.
• 1 vial x Factor VIII Inhibitor Free Plasma i.ads. 1 mL
  Factor VIII Inhibitor Free Plasma i.ads., to be dissolved in 1 mL distilled water. It serves as a negative control without Factor VIII Inhibitor.
• 1 vial x Imidazole buffer, sterile 17 mL.

The reagents for Factor VIII assay are not included.

Residual % Factor VIII Activity

A test sample has no inhibitor if the FVIII value of the test sample is the same as the value of the control mixture i.e. the % Factor VIII activity remaining after incubation is 100%.

Definition of Bethesda Unit

A test sample treated by the method above with a residual Factor VIII activity of 50% contains one Bethesda Unit of Factor VIII Inhibitor/mL.

Calculation

Using semi log graph paper, residual % FVIII activity is plotted against Bethesda Units/mL (Linear Axis). The residual % FVIII activity between 25% and 75% can then be read off and the number of units FVIII Inhibitor/mL is multiplied by the dilution factor to obtain the number of Bethesda units per mL in the sample.