Anticoagulant Therapy

More On Anti-Xa DOAC Variability

Click our 7-23-25 entry, Anti-Xa DOAC Variability for an 8-21-25 reference from Dr. Emmanuel Favaloro.

Anticoagulant Therapy

August 2025 QQ: Anticoagulant Choice for AFIB

Our August 2025 Quick Question asks, “What AC does your provider prescribe for non-valvular AFIB?” I (Geo) asked my PCP this question at my annual wellness visit on July 29, 2025. Not a personal concern, just curious. Please provide your answer on the right and add your comments, which will appear in our end-of-month summary.

Quick Question Archive

Anti-Xa DOAC Assay Variability

Click here to read an open-access article describing the variability in assay methodology when monitoring apixaban and rivaroxaban: Baker RM, Selby R, Moffat KA, et al. Investigating interassay variability between direct oral anticoagulant calibrated anti-factor Xa assays: a substudy of the perioperative anticoagulation use for surgery evaluation (PAUSE) trial. Res Pract Thromb Haemost. 2025;9:102899. doi: 10.1016/j.rpth.2025.102899. […]

Anticoagulant Therapy

What is Abelacimab?

In 2020 we posted news about a new anticoagulant osocimab, an early and ongoing effort to develop a monoclonal antibody that neutralizes FXI and FXIa. Click here for a press release from Anthos Therapeutics (formerly Blackstone Life Sciences) describing results from the AZALEA-TIMI 71 study that was discontinued early due to an overwhelming reduction in […]

Anticoagulant Therapy

April 2025 QQ Results: Measuring Warfarin in LAC Patients

Our April 2025 Quick Question asked, “How do you measure warfarin in a patient with LAC?” The poll drew 47 respondents and was a sequel to our March 2025 question, “How do you test for lupus anticoagulant?” that referenced the ISTH‘s most recent LAC guideline, Devreese KMJ, Bertolaccini ML, Branch DW, et al. An update […]

Quick Question Archive

Chromogenic FX Assay versus PT/INR

Here is an April 1, 2025, “Differential Discussions” webinar hosted by Malissa Norfolk, University of Maine Augusta, and David Cabral, University of Massachusetts Dartmouth. It features my colleague David McGlasson on the subject of “Comparison of the CFX Assay to the INR for Monitoring OAC Therapy.” Thank you to these three hemostasis experts for this […]

Anticoagulant Therapy

April 2025 Quick Question: How to Measure Warfarin in a LAC Patient

Our April 2025 Quick Question is a poll that asks, “How do you measure warfarin in a patient with lupus anticoagulant (LAC)?” This question is a sequel to our March 2025 question, “How do you test for lupus anticoagulant?” that references the ISTH‘s most recent LAC guidelines, Devreese KMJ, Bertolaccini ML, Branch DW, et al. […]

Lupus Anticoagulant

PT/INR Harmonization

Here is an open-access January 2025 publication that describes an organization-wide PT/INR harmonization effort. Click on the reference to obtain the article: Favaloro EJ, Arunachalam S, Chapman K, Pasalic L. Continued harmonization of the international normalized ratio across a large laboratory network: Evidence of sustained low interlaboratory variation and bias after a change in instrumentation. […]

Anticoagulant Therapy

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 […]

Anticoagulant Therapy

Reptilase Time

I received this question on 9/14/24: Hello George, Is there any condition where reptilase time is prolonged while thrombin time is normal? My answer is, in a word, no. The thrombin time (TT, or TCT) typically uses 50–100 mg topical human or bovine thrombin, mixed 1:1 with plasma. A normal plasma/thrombin mix clots within ~20 […]

Bleeding Disorders

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George Fritsma is a medical laboratory scientist, educator, and author. George is a member of the International Society on Thrombosis and Hemostasis, the International Society for Laboratory Hematology, and the American Society for Clinical Laboratory Science.

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