Diagnostic Use
Dabigatran is a direct oral thrombin inhibitor. A Dabigatran assay is used to quantify Dabigatrin levels and assess the anticoagulant effect when routine tests are unrelaible due to reagent sensitivity. Routine monitoring of Dabigatran is not recommended but may be required when the patient is bleeding, prior to urgent surgery, with renal impairment, suspected overdose or accumulation, and monitoring of reversal therapy. The Direct Thrombin Clotting Time (DTCT) and Dilute TCT + protamine are the most sensitive basic coagulation tests to demonstrate the presence of Dabigatran. DTCT/TCP are useful to prove the presence of Dabigatran either for compliance or pre-surgical clearance.
Interpretation
Routine monitoring of Dabigatran (Pradaxa) therapy is not recommended.
Compliance or clearance of this anticoagulant can be confirmed by requesting a Dilute Thrombin Clotting Time (DTCT). The DTCT is a very sensitive screening test for Dabigatran. Even very low levels of Dabigatran will prolong the DTCT. All the patients on a BD therapeutic dose of Dabigatran should have a DTCT of greater than 80 seconds. The DTCT will only return to normal (12 – 20 seconds) when Dabigatran has been totally cleared. The Dabigatran level will not be performed if the DTCT is normal. Please discuss with the Haematologist or Haematology Registrar if a dabigatran level is required with a normal DTCT.
A normal basic coagulation screen (PR and APTT) cannot exclude the presence of this anticoagulant.
There is no established therapeutic range for Dabigatran. Published data (PETRO study) based on 150 mg bd dosage showed mean peak levels of 180 ng/mL and mean trough levels of 90 ng/mL, however the range is very wide.
A level of <10 ng/mL should be safe for surgery, providing there are no other bleeding risks.
The assay result has to be interpreted in the context of the timing of the last dose.