Studies on PIVKA VII.

In 30 subjects on stabilized oral anticoagulant treatment, factor VII activity (VII:C) and factor VII antigen (VII:Ag) were evaluated. The average VII:C and VII:Ag levels were 8.7 and 30.7, respectively. All plasma samples were treated with 1 M barium chloride: all the activity and a corresponding average amount of antigen were adsorbed by the salt. The cold-promoted activation of factor VII was found in 5/30 subjects. Corresponding amounts of VII:C and VII:Ag were also removed from the plasma of these subjects after cold activation following the addition of barium chloride. It clearly results from these studies that a portion of VII:Ag cannot be adsorbed by barium chloride because of a reduction (or a lack) of the gamma-carboxyglutamic groups. This portion of VII:Ag can therefore be identified as Pivka VII.