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Lab Monitoring For a Patient Transitioning From DOAC to Heparin

From Jessica Warner, MLS (ASCP)cm
Technical Specialist
Network Coagulation Service
Lab Administration
Kettering Health

Hi George, Has there been much discussion on what sites are using for lab monitoring for patients transitioning from DOAC to heparin? We have strictly been using anti-Xa for heparin monitoring since 2015. We are a 13-site network with 8 hospitals that perform anti-Xa.
Doing an aPTT study is absolutely of no interest to me and for good reasons doesn’t seem like it can honestly be that accurate. We moved away from it because of its not always being great. Now adding another drug that may or may not affect the aPTT just doesn’t seem like a wise decision. My pathologist also had these concerns when pharmacy and doctors first asked for this approach.
I then suggested DOAC-Stop but pharmacy then realized it was not FDA cleared and they didn’t like that even though I would be the one in the lab doing a full validation study for it, they couldn’t come to terms with that. There biggest concern was I couldn’t find anyone else using it yet for the anti-Xa test except it was being used at some sites for special coagulation testing but nothing routine.
I then did some more digging and discovered that U of M and Corewell Health in Michigan are using the anti-IIa assay as an LDT. Duke is also working on it.
Our pharmacy has agreed to this but I’m having a little struggle with getting the setup just right on the ACL TOP platform. The locations in Michigan don’t have TOPs, Duke does, and I used their setup as the backbone but had errors on my calibration so I’m trying to clean those up.
I’m more curious just to find out if anyone else has picked up this route who also may have a TOP to pick their brain and work through it.
Not sure if you can put this into a poll question or what not but it is an interesting topic. Thanks!


Hello, Jessica, thanks for your question and comments. For our readers, click here to read our 2020 post describing DOAC-Stop, DOAC-Remove, and DOAC-Dipstick. These products labeled RUO in the US. Watch here for the next few days as our participants respond.


February 5, 2025: From colleague, author, and frequent Fritsma Factor participant Bob Gosselin: Hey GF, et al, this has been an issue with our pharmacy colleagues for a few years now.  I have given a few remote talks at the Pharmacy Innovations Conference on Antithrombotic Therapy (PICAT) conferences about this subject, and the one in 2023 sharing the virtual dais with Adam Cuker giving clinician and laboratorian perspectives and solutions. The presenters published Gosselin RC, Cuker A. Assessing direct oral anticoagulants in the clinical laboratory. Clin Lab Med. 2024;44:551-562. doi: 10.1016/j.cll.2024.04.014. PMID: 39089758, available from your facility’s library. Here is a helpful excerpt: “If the baseline APTT is prolonged and therefore cannot be used, alternatives for monitoring UFH anticoagulation in patients with circulating FXa DOAC include heparin-calibrated TCT with a target of 0.2 to 0.4 IU/mL or the use of either heparin neutralizing agents (ie, protamine sulfate or Dade Hepzyme®, Siemens Healthcare Diagnostics, Newark, DE) or DOAC neutralizing agents [such as DOAC-Stop® or DOAC-Remove®] to eliminate the contribution of one class of drugs. Any neutralizing method used should be locally verified to ensure intended effect and noninterference with assay performance in the absence of targeted drug.”


Jessica, see also the comments below from Drs. Ali Sadeghi-Khomami and Emmanuel Favaloro.

 

 

BG
Comments (2)
Anticoagulant Therapy
Dr. Emmanuel Favaloro
Feb 5, 2025 12:09am

I have a recollection reading somewhere (could have been a meeting abstract) a study using a DOAC absorbent to remove the DOAC to measure anti-Xa result due to residual heparin in a transitioning patient, but yes, in the USA DOAC-Stop is not yet FDA cleared, so I guess would end up being a LDT. Haematex, the maker of DOAC-Stop also have a heparin neutalising CaCl reagent that could be used to neutralise the heparin to measure residual DOAC presence and also DOAC-Stop can be used to remove the DOAC to measure residual heparin should an APTT be employed. Otherwise, anti-IIa assay for the residual heparin, but again maybe an LDT as well in the US.

Dr. Ali Sadeghi-Khomami
Feb 4, 2025 9:05pm

Dear Jessica, Direct Oral Anticoagulants (DOACs) is a general term encompassing both FIIa inhibitors (Dabigatran) and FXa inhibitors (Apixaban, Rivaroxaban). When transitioning a patient from a DOAC to heparin (UFH, LMWH, Fondaparinux), the anti-IIa LDT assay may not be the effective solution for Dabigatran, LMWH, or Fondaparinux. While DOAC-Stop is not FDA-cleared, several studies have shown minimal interference with heparins. Conducting your own validation study and supporting it with relevant publications, can help to justify its use.
Exner T, Ahuja M, Ellwood L. Effect of an activated charcoal product (DOAC Stop™) intended for extracting DOACs on various other APTT-prolonging anticoagulants. Clin Chem Lab Med. 2019;57:690-6. doi: 10.1515/cclm-2018-0967. PMID: 30427777.
Frans G, Meeus P, Bailleul E. Resolving DOAC interference on aPTT, PT, and lupus anticoagulant testing by the use of activated carbon. J Thromb Haemost. 201917:1354-62. doi: 10.1111/jth.14488. PMID: 31102433.

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