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Chromogenic Kits

Learn more about our Chromogenic Kits.

Phospholipid Emulsions

Our highly stable phospholipid emulsions are suitable for use in analyses related to procoagulant and anticoagulant pathways.


Rox Factor XIa

REF 110050

A chromogenic kit for quantitative activity determination of Factor XIa in enriched or highly purified protein preparations. Not intended for analysis of plasma

Measurement Principle

Human FXIa is determined from its activation of human Factor IX and ensuing activation of human Factor X. Generated Factor Xa is then measured with a chromogenic FXa substrate.

The activation of Factor IX is performed in two steps:

1. Initial activation of FIX in the absence of phospholipids.

2. Continued activation of FIX in the presence of FX and phospholipids, therewith allowing concomitant activation of FX.

- A chromogenic kit based upon FXa generation.

- 1 Kit = 2 x 50 test

- Detection Limit = about 0.03 mIU/mL

- No use of human plasma

Features of the Rox Factor XIa kit were presented at the 58th SSC meeting 2012 in Liverpool:



2018-06-29 Posters at the SSC meeting in Dublin July 18-21, 2018.

Steffen Rosén and Rossix AB will present two posters at the SSC meeting in Dublin:

PB229 - Overestimation of recombinant wild type FIX potency by a one-stage method indicated from comparison with a chromogenic FXIa and TF/FVIIa based methods and through discrepant activation of rwtFIX and plasma derived FIX by plasma kallikrein.

PB238 - Underassignment of FIX potency of rFIX-Albumin fusion protein by one-stage methods demonstrated in studies on FXIa and FIXa generation. 


2016-06-22 Publication in collaboration with NovoNordisk

Rosén P, Rosén S, Ezban M, Persson E.

Overestimation of N-glycoPEGylated factor IX activity in one-stage factor IX clotting assay owing to silica-mediated premature conversion to activated factor IX.

J Thromb Haemost 2016; 14: 1420-7.


2015-04-13 Publication in collaboration with AstraZeneca

Ann Lövgren et al. Blood Coagulation and Fibrinolysis, Characterization of thrombin derived from 

human recombinant prothrombin.

Open access: click here