Coumarin Plant Poisoning Workup

Updated: Mar 31, 2014
  • Author: Arasi Thangavelu, MD, FACEP, FAAEM; Chief Editor: Asim Tarabar, MD  more...
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Laboratory Studies

See the list below:

  • Obtain complete blood count, prothrombin time (PT) (expected to be normal if obtained shortly after ingestion), and International Normalized Ratio (INR).

    • Serial PTs at 24 and 48 hours postingestion should identify patients at risk of coagulopathy

    • The World Health Organization introduced INR in an effort to standardize the results of the PT test. Values of INR are independent of the reagents and methods and, therefore, are comparable between laboratories across the country and abroad. The INR is defined as the normal PT ratio that would result if the World Health Organization's primary international thromboplastin were used to test the patient's sample. INR = (Patient PT/ normal PT) ISIISI is the International Sensitivity Index of the thromboplastin used in the local laboratory.

  • A high performance liquid chromatographic method can be used to detect and quantify serum levels of the following 5 anticoagulant rodenticides: brodifacoum, bromadiolone, coumatetralyl, difenacoum, and warfarin. Warfarin and superwarfarin levels may be obtained; however, these specialized tests generally are not helpful in the ED setting.

  • In cases of surreptitious hydroxycoumarin use, vitamin K-2, -3 epoxide and vitamin K can be measured. Elevated levels of vitamin K-2, -3 epoxide suggest block of reductive step by a hydroxycoumarin.

  • Fresh frozen plasma provides active anticoagulation factors in patients with significant active bleeding.

  • Type and crossmatch packed red cells in patients with hemodynamic compromise or significant blood loss.


Imaging Studies

If intracranial hemorrhage is suspected, consider CT scan of the head.