FXa-based chromogenic assay consisting of liquid components for quantifying functional Antithrombin activity in human citrated plasma.

Antithrombin (AT) activity is measured in citrated plasma for diagnosis of AT deficiency. MediRox AT liquid reagent is a ready-to-use chromogenic kit based on bovine FXa and chromogenic FXa substrate.

Liquid components, ready to use

FXa-based AT assay

Excellent reagent stability

Sensitive to low levels AT

Insensitive to Heparin Cofactor II 


General Description

AT is the primary physiological inhibitor of thrombin and FXa in plasma, and thereby effectively regulates blood coagulation. An inherited AT deficiency is often associated with thromboembolic disease, and acquired deficiencies may occur in liver disease and disseminated intravascular coagulation.

Performance Characteristics

AT activity is determined in a two-stage chromogenic assay as follows:

An excess of FXa is added to citrated plasma in the presence of heparin. The residual FXa activity is determined from the hydrolysis of a chromogenic FXa Substrate, which results in the release of free p-nitroaniline (pNA). The amount of pNA is measured by absorbance at 405 nm and the result is inversely proportional to the amount of AT present in citrated plasma, and expressed as % AT activity.

Hep + citrated plasma (AT) + FXa (excess) —–> Hep-AT-FXa + FXa residual

FXa residual + Chromogenic Substrate      —–> pNA + peptide

Sensitivity & Specificity

Details & Typical Data

Product form: Liquid components
Sensitivity: Linear calibration from 0,80-1,20 IU/mL
Specificity: No affect by Heparin Cofactor II activity, no affect by UF and LMW heparin <4,0 U/mL; Bilirubin <0,4 mg/mL; triglycerides <5ng/mL; hemoglobin <1,5 ng/mL

Stability & Storage

Storage: 2-8 °C
Shelf life: 24 months at 2-8 °C
Open vial stability: 30 days at 2-8 °C

Ordering Information

Reference Number Product Description Pack Size
MRX1200 Antithrombin Liquid Kit 6x6 mL FXa Reagent + 3x3 mL Substrate
MRX1201 Antithrombin Calibrator 1x1 mL
MRX1202 Multi Calibrator I (AT, Fib, DD) 1x1 mL
MRX1202-10 Multi Calibrator I (AT, Fib, DD) 10x1 mL
MRX1203 Multi Calibrator II (AT, Fib, PTQ) 1x1 mL
MRX1203-10 Multi Calibrator II (AT, Fib, PTQ) 10x1 mL
MRX171 Eximius Control Basic, L1 10x1 mL
MRX172 Eximius Control Basic, L2 10x1 mL
MRX173 Eximius Control Basic, L3 10x1 mL
MRX181 Eximius Control PLUS, L1 10x1 mL
MRX182 Eximius Control PLUS, L 2 10x1 mL
MRX183 Eximius Control PLUS, L3 10x1 mL
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