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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 Prothrombin

REF 200040

For quantitative determination of Prothrombin (FII) functional activity in plasma and FII containing concentrates. The method is suitable for plasma collected in citrate or EDTA.

- A chromogenic Prothrombin method based upon the prothrombinase complex.

- non-γ-carboxylated-FII is not activated in the method in contrast to snake venom based prothrombin methods.

- 1 Kit = 4 x 25 test

- Detection Limit = about 0.05 U/mL (5%) when using a plasma dilution of 1:200 as   prescribed in the package insert. The detection limit for undiluted samples is about 0.25 mU/mL.

Measurement Principle

FII functional activity is determined in a chromogenic prothrombinase method, in which human FII is activated to thrombin (FIIa) by human FXa in the presence of bovine FV, calcium ions and phospholipid.

The amount of FIIa formed is determined from the hydrolysis of a chromogenic FIIa substrate. The FII activity of the sample is assigned vs. plasma or a FII concentrate standard with FII potency expressed in International Units (IU).

The prothrombinase complex is sensitive to g-carboxylation and therefore non-γ-carboxylated-FII is not activated in this method in contrast to snake venom based prothrombin methods.



2019-06-20 ISTH, Melbourne July 6-10, 2019.

Rossix will present three posters related to analysis of Factor IX at the ISTH in Melbourne:

PB0099 - Evaluation of Lupus Anticoagulant interference in a chromogenic Factor IX kit for determination of

Factor IX activity

PB1294 - Assessment of Factor IX Padua activity with a one-stage clotting method and with FXIa- and tissue factor/FVIIa-based chromogenic methods

PB1295 - Recombinant Factor IX fused with albumin (rFIX-HSA) is underassigned by one-stage methods with silica as contact activator

More information


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