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Nijmegen-Bethesda Test Volumes

This is a follow-up to our 9-30-24 post introducing our October Quick Question, “At what FVIII activity level do you order a Nijmegen-Bethesda inhibitor assay (NBA)?” It occurred to me (Geo) that the demand for NBAs has diminished with the advent of the FVIII bypassing therapies, HemLibra® (emicizumab), soon to be followed by MIM8 and […]

Bleeding Disorders

October 2024 Cheat Sheet

Click here for your October 2024 Cheat Sheet. You will receive your email copy of the Cheat Sheet in a few days. Thank you for your continued Fritsma Factor interest.

October 2024 Quick Question: Inhibitors

A 9/5/24 question from Chad Siniard, MD, director of the University of Alabama at Birmingham Hospital coagulation service, generated a discussion on the FVIII level that a facility chooses to generate an order for a Nijmegen-Bethesda FVIII inhibitor assay. Our October 2024 Quick Question (on the right} is a poll that asks, “At what FVIII […]

Bleeding Disorders

September 2024 Quick Question Response

Our September 2024 Quick Question drew 59 responses and asked: “At what FVIII activity level should the PTT become prolonged?” Our answers were: 60 U/dL: 6 (10%) 40 U/dL: 37 (63%) 10 U/dL: 12 (20%) 1 U/dL: 4 (7%) Most of us chose the correct answer. The PTT “partial thromboplastin” manufacturers develop their reagent to […]

Bleeding Disorders

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

World Thrombosis Day, October 13

Dear George, As World Thrombosis Day (WTD) approaches on October 13, we’re excited to share new resources to help make this year’s campaign more impactful. Your participation is essential to raising awareness about thrombosis, and we are grateful for your continued support. To help you engage your community, we’ve added new tools and materials. New […]

FVIII Level and Inhibitor Studies

From Chad Siniard, MD, University of Alabama at Birmingham (UAB) Hospital Laboratory Medicine. George, We have a FVIII activity level that is exactly 30%. We haven’t documented an official level for triggering an inhibitor titer, though our coag lab scientist Laura Taylor customarily runs an inhibitor assay if the result is <30%. We assayed using […]

September 2024 Cheat Sheet

Here’s your September 2024 Cheat Sheet. If you want to receive a copy of your personal cheat sheet, please fill out the Fritsma Factor Post Page form. As always, we welcome your comments.

September 2024 Quick Question: PTT

I (Geo) prefer PTT to APTT or aPTT because the “A” or “a” is superfluous. Laboratory scientists no longer offer an “unactivated” PTT. The “partial thromboplastin” reagent consists of a phospholipid or combination of phospholipids that may include animal, plant, or synthetic sourced phosphatidylserine, phosphatidylcholine, phosphatidylinositol, sphingomyelin, and/or phosphatidylethanolamine. Accompanying the phospholipid is one of […]

August 2024 Quick Question Summary: Rebalancing Therapy

Our August 2024 Quick Question, which attracted 18 responses, asked, “Which hemophilia ‘rebalancing’ therapy suppresses antithrombin RNA production?” Here are your answers: Efanesoctocog alfa: 0 Concizumab: 3 (17%) Octavian 2 (11%) Hemgenix 3 (17%) Fitusiran 10 (55%) Rebalancing therapy is the name for using RNA inhibitors (RNAi) that suppress mRNA synthesis, subsequently suppressing selected molecules. […]

Bleeding Disorders

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George Fritsma is a medical laboratory scientist, educator, and author. George holds faculty appointments with Rutgers University and Michigan State University, and is a member of the International Society on Thrombosis and Hemostasis, American Association of Clinical Chemists, and American Society for Clinical Laboratory Science.

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Quick Question