title: Factor XII assay with the chromogenic substrate chromozym PK.
abstract: A chromogenic assay for the determination of factor XII using the chromogenic substrate Chromozym PK was evaluated. The assay was linear in the range 10 U/l to more than 200 U/l. Using the assay, the normal range of factor XII (50 healthy volunteers at random) was 136 U/l +/- 27 U/l. Kallikrein-inhibiting concentrations of aprotinin did not influence factor XII. Comparison of the chromogenic with the clotting assay resulted in a correlation coefficient of r = 0.831 (p-value less than 0.001). In patients with deep vein thrombosis, factor XII level was found to be reduced to about 60% of normal activity.
mesh_terms: D000328:Adult; D000368:Aged; D007611:Aprotinin / Q000494:pharmacology; D001793:Blood Preservation; D002863:Chromogenic Compounds; D004355:Drug Stability; D005174:Factor XII / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides; D010783:Photometry / Q000379:methods; D013918:Thrombin Time; D013924:Thrombophlebitis / Q000097:blood* / Q000175:diagnosis
chemical_list: D002863:Chromogenic Compounds; D009842:Oligopeptides; C031694:Chromozym PK; D005174:Factor XII; D007611:Aprotinin