Bovine Factor Xa Solution

Reconstitute bovine coagulation factor Xa as directed by the manufacturer and dilute with tris-chloride buffer pH 7.4. Any change in the absorbance of the solution, Appendix II B, measured at 405 nm using tris-chloride buffer pH 7.4 in the reference cell, is not more than 0.15 to 0.20 per minute.