Factor X I I Assay with the Chromogenic Substrate Chromozym PK ® *)

Summary: 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 aproti-nin did not influence factor XII. Comparison of the chromogenic with the clotting assay resulted in a correlation coefficient of r = 0.831 (p-value < 0.001). In patients with deep vein thrombosis, factor XII level was found to be reduced to about 60 % of normal activity. Ein photometrisches Verfahren zur Faktor ΧΠ-Bestimmung mit dem chromogenen Substrat Chromozym PK® Zusammenfassung: Es wird ber ein photometrisches Verfahren zur Faktor XII-Bestimmung mit dem chromogene