Anticoagulant testing

Monitoring of Heparin and Direct Oral Anticoagulants

Heparin is one of the oldest molecules discovered to have anticoagulant properties. Nowadays it is frequently used in hospitals as treatment. Whether it is Unfractionated (UFH), Low Molecular Weight Heparin (LMWH) or a heparin analogue (Orgaran & Arixtra), the follow-up of heparin is of routine practice for laboratories. Besides heparin, Direct Oral Anticoagulants (DOACs) are now commonly used anticoagulants and laboratory testing of DOACs has become a routine procedure. NODIA works with several suppliers to provide hands on solutions for testing under specific conditions.

Hyphen BioMed  took the lead  in laboratory testing of DOACs. They provide kits for quantification of DOAC levels with great accuracy in patient plasma. The most commonly used kits for the purpose of direct oral anticoagulant testing are the HEMOCLOT™ Thrombin Inhibitor for Anti-IIa molecules and BIOPHEN Heparin LRT for the anti-Xa measurements. Until recently Hyphen’s anti Xa kit, BIOPHEN Heparin LRT, could not make a difference between heparin and DOACs. BIOPHEN DiXaI which is specific for anti-Xa DOACs was the best solution so far. Today it is possible to measure DOACs without influence of heparin with the BIOPHEN Heparin LRT by using a specially developed Heparin Neutralizing Buffer.

In order to comply with current regulations, Hyphen BioMed supplies CE-IVD marked applications for these methods  on the most common coagulation analysers.

For a rapid qualitative testing on the presence of DOACs in whole blood  our partner Enicor developed active tip technology assays on their ClotPro thromboelastometer. The screening RVV-test is based on an activation of coagulation by the Russel Viper Venom. In the presence of a DOAC the clotting time will be prolonged.  A differentiation between anti-Xa and anti-IIa inhibitors can be made with a second test: the ECA-test. Here the coagulation is activated with ecarin on the level of prothrombin. Here, only anti-IIa inhibitors will show a prolongated clotting time. The use of active tip technology makes it very easy to perform the assay in emergency situations. Both assays (RVV-test and ECA-test) are now CE-IVD labelled.

If DOACs  interfere with your laboratory assays, 5-Diagnostics provides DOAC-Remove™ aswell as DP-Filter to easily remove DOACs from the samples.

Reagents for Heparins and their analogues

  • BIOPHEN™ Heparin LRT: Chromogenic assay for quantitative determination of anti-Xa activity. Liquid reagent, ready to use.

Reagents for Direct Factor Xa Inhibitors

  • BIOPHEN™ Heparin LRT: Chromogenic assay for quantitative determination of anti-Xa activity. Liquid reagent, ready to use.
  • BIOPHEN™ DiXaI: Chromogenic assay for quantitative determination of anti-Xa activity.

Reagents for Direct Thrombin Inhibitors (DTIs)

ClotPro reagents for screening of DOACs in whole blood

  • RVV-test: Highly sensitive to direct oral anticoagulants.
  • ECA-test: Highly senitive to direct thrombin antagonists.

Other products

- A new concept for highly performing chromogenic assays -

Introduction

Apart from the molecular differences between LMWH and UFH, our partner HYPHEN BioMed developed a way to measure both on a single CE-IVD application: the BIOPHEN™ Heparin LRT. This kit is the result of a superposition of the two individual curves onto each other, which makes it possible to measure LMWH and UFH using a single calibration curve. The kit is not the result of a simple combination of both sets of calibrators, so there is no risk of losing accuracy in the extremes.

The BIOPHEN™ Heparin LRT kits can also be used for the monitoring of DOACs (Direct F-Xa inhibitors) such as Rivaroxaban, Apixaban and Edoxaban. The assay dilutions need to be adapted and a dedicated calibration is mandatory. Contact us for more information about the possibilities.

BIOPHEN™ Heparin LRT kits are available in three different sizes: 4 x 7.5 ml4 x 5 ml and 3 x 3 ml.

NODIA's choice

Recommended product for all your routine lab anti-Xa testing

Tips

  • To avoid any interference from heparin like substances in the measurement of DOACs, we recommend the use of the Heparin Neutralizing Buffer.

Reaction principle

Major Features

  • Anti-Xa Chromogenic method
  • Ready-to-use Liquid Reagents (rapid results)
  • For testing Heparin and Heparin-like anticoagulants (Orgaran & Arixtra)
  • Using the same calibration curve for UFH and LMWH
  • Validated methods for testing direct FXa inhibitors (DOACs)
  • Comprehensive range of kits, standards and controls

BIOPHEN™ DiXaI

- Direct factor Xa inhibitor assay -

Introduction

BIOPHEN™ DiXal is a chromogenic method for the quantitative measurement of Direct Factor Xa inhibitors such as Rivaroxaban and Apixaban.

Major Features

  • No matrix effect
  • Highly robust
  • Insensitive to heparin or heparin like substances
  • CE labeled for IVD

HEMOCLOT™ Thrombin Inhibitors

- Clotting assay for the quantitative determination of DTI activity in plasma -

Introduction

Direct Thrombin Inhibitors (DTI) have increased prophylactic or curative applications. New oral DTI’s, like dabigatran etexilate, are being introduced as a safe alternative for the treatment with vitamin K antagonists or with low molecular weight heparin. 

In acute situations a good laboratory method for the determination of the kinetics of the drug in the human body is needed. This method has to be free of interference by plasmatic factors and should have an optimised sensitivity in the therapeutic range. 

The Ecarin Clotting Time (ECT), the aPTT and the PT have been proposed but have a too variable sensitivity and are insufficiently reliable. These methods are sensitive to variations in clotting factors and are not able to measure high (> 0.2 mg/ml) DTI concentrations. 

HEMOCLOT™ Thrombin Inhibitors is a calibrated clotting assay, without matrix effects, that allows an accurate and sensitive determination of DTI’s, both in lox as in high concentrations.

The HEMOCLOT™ Thrombin Inhibitors kit offers together with the Dabigatran Plasma Calibrator and Controls a complete package for the laboratory determination of Dabigatran etexilate.

Major Features

  • Clotting method
  • Linear dose-response curve
  • Uses highly purified human α-thrombin
  • Optimized for the determination of dabigatran etexilate
  • No interference of prothrombin or fibrinogen concentration
  • Reproducible and consistent from run to run and from lot to lot

DTI: Mode of action

Dabigatran Calibration

Dabigatran Plasma Calibrator is a set of calibration plasma’s for the determination of dabigatran. These plasma’s are titrated and optimised for the use with HEMOCLOT™ Thrombin Inhibitors.

Dabigatran is the active component of the oral pro-drug dabigatran etexilate. The calibration is a set of 3 different concentrations of dabigatran in plasma. These concentrations are accurately determined against an internal reference standard and are confirmed with HPLC. The clotting time obtained is plotted as a function of the dabigatran concentration of the calibrator.

The calibration curve is linear from < 0.5 up to 0.50 mg/ml. Patients under dabigatran are usually found in this concentration range.

Dabigatran Control

Dabigatran Control Plasma consists of plasma’s with two different dabigatran concentrations. These controls can be used to validate the calibration curve and to control the stability of the reagents.

Method

  • Citrate plasma of the patient is 1:8 diluted with a 0.15 M physiological NaCl solution or with an Imidazole buffer. For high concentrations an alternative 1:20 dilution can be applied.
  • Normal Pool Plasma (R1) is mixed with diluted test plasma and incubated at 37°C.
  • Clotting is activated by the addition of a constant amount of highly purified human α-thrombin and calcium.
  • The measured clotting time has a direct linear relationship to the concentration of the DTI in the plasma.
 

Automated methods: This method is easy to adapt on automated systems. Validated applications are available for the most common coagulation analysers. Contact us for more information.

BIOPHEN™ DTI

- Chromogenic assay for quantitative determination of DTI activity -

Introduction

Quantitative assay for measuring the anti-IIa activity of hirudin and other Direct Thrombin Inhibitors (DTIs) in human citrated plasma, using a chromogenic method.

BIOPHEN™ DTI reagent contains an heparin neutralizing substance: the assay can be run on heparinized samples. No significant interference is observed up to 2 IU/ml UFH or LMWH in plasma.

Features

  • Specialized calibrated chromogenic assays, fully automatize, with CE-IVD applications for all major analyzers
  • No matrix effect, accurate and sensitive at low and high concentration ranges
  • Developed for quantitation of various DTI’s.

ClotPro RVV- and ECA-test

- ClotPro reagents for screening of DOACs in whole blood -

Where the RVV-test is a rapid screening test that uses a direct activation of FXa with a high sensitivity to direct oral anticoagulants and other thrombin antagonists., the ECA-test makes use of a direct activation of thrombin, with a high sensitivity and specificity for thrombin antagonists. The combination of these two test allows for a rapid detection and differentiation between anti-FXa and thrombin antagonists in urgent situations.

Ready to use system reagent for the detection of factor Xa (FXa) antagonists in citrated blood on the ClotPro system. CaCl2 recalcifies the sample and reagent derived from Russells viper venom (RVV) activates FX in the sample to FXa. This FXa triggers coagulation and clot formation.

ECA-test is a ready to use system reagent for the detection of dabigatran in citrated blood for the ClotPro analyzer. Ecarin, a thrombin activator derived from the venom of the saw-scaled viper (Echis carinatus) activates prothrombin from the blood sample. Polybrene is added to the reagent to antagonize heparin that may be present in the sample.

DOAC removal

- For removal of DOACs from plasma specimens -

Diagnostic laboratories often face problems since the presence of Direct Oral Anticoagulants (DOACs) in human plasma samples interfere with various hemostasis assays. DOAC-Remove™ together with DP-Filter®  are intended to be used for the removal of Direct Oral Anticoagulant (DOAC) compounds from human citrated plasma samples, including dabigatran, rivaroxaban, apixaban, edoxaban and argatroban.
  • Both products reduces the false positivity for lupus anticoagulants and is useful for eliminating interference on routine coagulation assays such as APTT, PT, TT, single factors, chromogenic assays and APC-R.
  • No significant effect on clotting factors has been reported.
  • One tablet of DOAC-Remove™ neutralizes the influence of DOACs in 1mL (range 0.5 to 2 mL) citrated plasma sample.
  • After incubation and centrifugation, the plasma supernatant can immediately be used for hemostasis assays, or it can be frozen respectively.
  • DOAC-Remove™ has a 5 year shelf life.
  • One DP-Filter® is capable of removing DOAC concentrations from up to 1,000 ng/mL.
  • No extra centrifugation step is needed.
  • Ready to use.
  • Easy to perform.