Bleeding Disorders

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 may have diminished with the advent of the FVIII bypassing therapies, HemLibra® (emicizumab), soon to be followed by MIM8 […]

Bleeding Disorders

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: PTT and FVIII Level

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

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 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

Extended Life Cryoprecipitate Fibrinogen

As reported by Amy Carpenter quoting Jay Hudgins, DO, MS, director of hemostasis and thrombosis, Department of Pathology and Laboratory Medicine, Nationwide Children’s Hospital, Columbus, Ohio, USA in the August 2024 edition of CAP Today, extended-life cryoprecipitate has several applications. INTERCEPT®, is the Cerus, Inc. trademark for their materials that crosslink and inactivate bacterial and […]

Bleeding Disorders

Measuring Current Hemophilia A and B Therapy

Click here for a comprehensive open-access review of the means for measuring current hemophilia A and B therapy: Bowyer AE, Gosselin RC. Factor VIII and factor IX activity measurements for hemophilia diagnosis and related treatments. Semin Thromb Hemost. 2023;49:609–20. doi: 10.1055/s-0042-1758870. PMID: 36473488; PMCID: PMC10421651.

Bleeding Disorders

August 2024 Quick Question: Hemophilia Treatment

Several hemophilia A or B treatments are in development or have been approved since 2021. Among these are the “rebalancing” preparations that suppress control proteins such as tissue factor pathway inhibitor (TFPI), antithrombin (AT), or activated protein C (APC). Rebalancing preparations are designed to compensate for the bleeding tendencies in FVIII or FIX deficiency without […]

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.

Cheat Sheets from George

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