Antithrombin

Assay overview

When it comes to laboratory antithrombin tests, NODIA has it all. Find out more about our tests on this antithrombin specific page.

General information

Classification of Antithrombin deficiencies

Congenital Antithrombin deficiencies can be classed in 4 different groups:

    • Type I: Decreased Antithrombin antigen concentration and decreased Antithrombin activity.
    • Type II: Decreased Antithrombin activity but normal antithrombin antigen.
      • Type II Subtypes:
      • RS (Reactive Site): Normal Antithrombin antigen concentration and decreased biological activity; a protein abnormality is present at the active site.
      • Type II HBS (Heparin Binding Site): Normal Antithrombin antigen concentration, normal Antithrombin activity in the absence of heparin, but decreased in its presence. An abnormality lies in the Heparin-AT bond. Can be detected with progressive AT activity assays. 
      • Type II (Pleiotropic): Decreased Antithrombin activity in combination with a lowered antigen level.
    •  

Functional assay of AT associated with an immunoassay allows to characterize the deficiency type

Biochemistry

Antithrombin is a single chain glycoprotein synthesized in the liver and has a molecular weight of about 58.200 daltons. Its concentration in normal plasma is about 125µg/ml. The half life is 2-3 days. 

AT is a direct inhibitor of thrombin (factor IIa) and Factor Xa, but also of other serine proteases, such as factor IXa, XIa and XIIa, plasmin and kallikrein.

Heparin accelerates dramatically the inhibition of Thrombin and Factor Xa. The Antithrombin concentration, like Protein C and Protein S concentrations, plays an important role in the hemostatic balance

- Anti Xa Chromogenic assay for measuring Antithrombin -

Introduction

BIOPHENTM AT anti-(h)-Xa LRT kit is a chromogenic one stage assay for the in vitro quantitative determination of Antithrombin (AT) activity on human citrated plasma using an anti-Xa method, manual or automated.
Reagents are in the liquid presentation, ready to use.

NODIA's choice

Recommended product for all your routine lab anti-Xa testing

Reaction principle
Biophen AT anti-h-Xa LRT
Intended use

Diagnosis of congenital or acquired Antithrombin deficiencies.

Major Features
  • Ready-to-use liquid reagent technology
  • All Human Factors
  • High on board stability
  • Insensitive for heparin
  • Automation protocols available
Tip

Avoid DOAC interference through the use of DOAC-Remove or DP-Filter

BIOPHENTM AT anti-(h)-Xa LRT assay is a kinetics method based on the inhibition of Factor Xa, which is at a constant concentration and in excess, by Antithrombin, in presence of heparin. The remaining Factor Xa is then measured by its amydolitic activity on a Factor Xa specific chromogenic substrate, which releases pNA. The amount of pNA generated is inversely proportional to the Antithrombin concentration present in the tested plasma.

- Anti Xa Chromogenic assay for measuring Antithrombin -

Introduction

BIOPHENTM AT (LRT) kit is a chromogenic one stage assay for the quantitative determination of the heparin cofactor activity of Antithrombin (AT) in human citrated plasma using an anti Xa method, manual or automated. This method uses Bovine reagents that are liquid and for this ready to use.

NODIA's choice

Recommended product for STA-R users for routine lab anti-Xa testing

Reaction principle
Biophen AT anti-h-Xa LRT
Intended use

Diagnosis of congenital or acquired Antithrombin deficiencies.

Major Features
  • Ready-to-use liquid reagent technology
  • High on board stability
  • Insensitive for heparin
  • Automation protocols available
TIP
Avoid DOAC interference through the use of DOAC-RemoveTM or DP-Filter

The BIOPHENTM AT (LRT) assay is a kinetic one stage assay based on the inhibition of Factor Xa, which is at a constant concentration and in excess, by Antithrombin in presence of heparin. The remaining Factor Xa is then measured by its amydolitic activity on a Factor Xa specific chromogenic substrate, which releases pNA. The amount of pNA generated is inversely proportional to the Antithrombin concentration present in the tested plasma.

Due to the assay’s insensitivity to heparin, plasmas from patients on heparin therapy may be tested.

- 2 Stage Heparin Anti-IIa Chromogenic assay for measuring antithrombin -

Introduction

Antithrombin (AT) is the major physiological coagulation inhibitor. When complexed to heparin, AT becomes a potent and fast acting inhibitor of different coagulation serine esterases. This anti-IIa assay thus measures the heparin dependent anti-IIa activity of AT.

Reaction Principle

The BIOPHENAT (Anti-IIa) method is an two stage assay based on the inhibition of a constant and in excess amount of Thrombin (IIa), by the tested AT in presence of an excess of heparin, and hydrolysis of a Thrombin specific chromogenic substrate, by Thrombin in excess. pNA is then released from the substrate. The amount of pNA released (measured by absorbance at 405nm) is then representative for the residual Thrombin quantity. There is an inverse relationship to the concentration of AT present in the tested sample.

Variant Method: Progressive Antithrombin Activity

For the identification of type II abnormality, Heparin Binding Site (HBS), a variant method can be performed using a specific “Tris buffer without heparin” (AR104A) instead of “R3 buffer”. 

A specific calibration curve must be done with BIOPHEN™ Plasma Calibrator and the patient AT activity (HBS) is directly read on the curve. The specific protocol is available upon request. In presence of the HBS variant, the patient has a normal AT activity with this method.

- 2 Stage Heparin Anti-Xa Chromogenic assay for measuring antithrombin -

Introduction

The BIOPHEN™ Antithrombin kit is a chromogenic assays for the in vitro quantitative determination of the heparin cofactor activity of Antithrombin (AT) in human citrated plasma using an anti Xa method.
Reaction principle
Biophen AT anti-h-Xa LRT

The BIOPHEN™ Antithrombin method is a kinetic two stage assay with it’s main principle based on the inhibition of FXa, which is at a constant concentration and in excess, by AT in presence of heparin. The remaining FXa is then measured by its amydolitic activity on a FXa specific chromogenic substrate, which releases pNA. The amount of pNA generated is inversely proportional to the AT concentration present in the tested plasma.
Due to the assay’s insensitivity to heparin, plasma from patients on heparin therapy may be tested.

Variant Method: Progressive Antithrombin Activity

For the identification of type II abnormality, HBS (Heparin Binding Site), a variant method can be used. The Bovine FXa vial must be restored with 2.5 mL of Tris buffer (AR103), without heparin.

A calibration curve must be done with the BIOPHEN™ Plasma Calibrator and the patient AT activity (HBS) is directly read on the curve. The specific protocol is available upon request.

In presence of the HBS variant, the patient has a normal AT activity with this
method.

The LIAPHEN™ AT kit is an immuno-turbidimetric assay using latex particles, for the in vitro determination of   antithrombin (AT). When the tested specimen is mixed with the reaction buffer (R2) and the latex reagent (R1), the anti-AT antibodies coupled onto latex particles react with AT present in the sample and agglutination occurs. The amount of  agglutination is directly proportional to the amount of AT in the sample and is measured by light absorption.
Reaction principle
Major features
  • Adaptations to the various automates are available
  • High on board stability
  • No hook effect is observed for AT concentrations below 200%

FYI: The AT antigen concentration measured in serum is 20 to 30% lower compared to plasma. The AT concentration measured in serum with the Liaphen AT is higher than the AT concentration measured with a functional assays due to AT consumption during clotting, whilst it will be identical to the concentration found in plasma.

An antithrombin concentration ≤ 70% indicates the presence of a quantitative deficiency, which must be confirmed by another test and/or by testing another plasma sample from the patient.

DIY

Human Antithrombin Neutralization, Mached Pair Antibodies can be used to inactivate (neutralize) the ability of ATIII to inhibit thrombin or activated factor X, even in the presence of heparin.

Antithrombin Deficient plasma

Both Lyophilized and Frozen Human Antithrombin Deficient Plasmas are available for any in vitro protocol or research study where a source of human ATIII deficient plasma is required. 

  •  
FYI

By definition, a 100% AT concentration corresponds to the concentration in a normal human citrated plasma pool, obtained by pooling plasmas from healthy males or females aged from 18 to 55 years, and out of any medication. The level of AT in healthy adults is usually comprised between 80 and 120%.

Product overview

ReferenceProduct namePackagingCategoriesManufacturer
221111BIOPHEN™ Antithrombin LRT4 x 70 testsChromogenic AssaysHYPHEN Biomed
221123BIOPHEN™ Antithrombin Anti-(h)-Xa LRT – small3 x 3mlChromogenic AssaysHYPHEN Biomed
221127BIOPHEN™ Antithrombin Anti-(h)-Xa LRT – large4 x 7.5mlChromogenic AssaysHYPHEN Biomed
221122BIOPHEN™ Antithrombin (Anti-IIa)2 x 2.5mlChromogenic AssaysHYPHEN Biomed
221102BIOPHEN™ Antithrombin (Anti-Xa) 2.52 x 25 testsChromogenic AssaysHYPHEN Biomed
221105BIOPHEN™ Antithrombin (Anti-Xa) 54 x 50 testsChromogenic AssaysHYPHEN Biomed
120002LIAPHEN™ Antithrombin (ATIII)2 x 40 testsTurbidimetric Latex Immuno AssaysHYPHEN Biomed
222101BIOPHEN™ Plasma Calibrator12 x 1mlCalibratorsHYPHEN Biomed
223201BIOPHEN™ Normal Control Plasma12 x 1mlControlsHYPHEN Biomed
223301BIOPHEN™ Abnormal Control Plasma12 x 1mlControlsHYPHEN Biomed
5D-42104FHuman Antithrombin Deficient Plasma, Frozen1mLDeficient & Inhibitor Plasmas5-Diagnostics
5D-42104LHuman Antithrombin Deficient Plasma, Lyophilized1mLDeficient & Inhibitor Plasmas5-Diagnostics
5D-42246FHuman Antithrombin-Heparin Cofactor II Deficient Plasma, Frozen1mLDeficient & Inhibitor Plasmas5-Diagnostics
5D-42246LHuman Antithrombin-Heparin Cofactor II Deficient Plasma, Lyophilized1mLDeficient & Inhibitor Plasmas5-Diagnostics
PP004AHuman Antithrombin III – small150µg (1PEU)Proteins & EnzymesHYPHEN Biomed
PP004KHuman Antithrombin III – small x6 6 x 150ugProteins & EnzymesHYPHEN Biomed
PP004BHuman Antithrombin III – medium1.5mg (10PEU)Proteins & EnzymesHYPHEN Biomed
PP004LHuman Antithrombin III – medium x1010 x 1.5mg (10PEU)Proteins & EnzymesHYPHEN Biomed
PP004DHuman Antithrombin III – large3.75mg (25PEU)Proteins & EnzymesHYPHEN Biomed
PP004MHuman Antithrombin III – large x1010 x 3.75mg (25PEU)Proteins & EnzymesHYPHEN Biomed
PP004CHuman Antithrombin III – extra large10mg Grade 1Proteins & EnzymesHYPHEN Biomed
AR103ATris Buffer Anti-Xa (progressive Antithrombin)10mlAuxiliary ReagentsHYPHEN Biomed
AR104ATris Buffer Anti-IIa (Progressive Antithrombin)10mlAuxiliary ReagentsHYPHEN Biomed
5D-10104GAnti-human Antithrombin III (ATIII), Goat, Purified IgG10mgAntibodies5-Diagnostics
5D-10104SAnti-human Antithrombin III (ATIII), Sheep, Purified IgG10mgAntibodies5-Diagnostics
5D-11104GAnti-human Antithrombin III (ATIII), Goat, Affinity Purified IgG0.5mgAntibodies5-Diagnostics
5D-11104SAnti-human Antithrombin III (ATIII), Sheep, Affinity Purified IgG0.5mgAntibodies5-Diagnostics
5D-15104SAnti-human Antithrombin III (ATIII), Sheep, Affinity Purified HRP Conjugated IgG0.1mgAntibodies5-Diagnostics
5D-17104SAnti-human Antithrombin III (ATIII), Sheep, Affinity Purified Biotinylated IgG0.1mgAntibodies5-Diagnostics
5D-181045-EIA Anti-human Antithrombin, Matched Pair Antibodies5 platesAntibodies5-Diagnostics
5D-182355-EIA Anti-human Thrombin-Antithrombin Complex, Matched Pair Antibodies5 platesAntibodies5-Diagnostics