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

Low Titer Group O Whole Blood in Trauma

Click here for a July 2024 CAP Today article describing the growing use of low titer group O whole blood in trauma and emergencies and its effect on trauma-induced coagulopathy.

Bleeding Disorders

Bioengineered FVIII: efanestocog alfa

Here is a richly illustrated open-access editorial of the development and physiologic function of efanesoctocog alfa (Altuviiio®, Sanofi), which features a half-life 4X that of current concentrates: Chowdary P. Bioengineered factor VIII–more innovation for Hemophilia A. N Engl J Med. 2024;391:277–82. doi: 10.1056/NEJMe2313795. PMID: 39018538.

Bleeding Disorders

Concizumab, A “Rebalancing Agent”

Below is the abstract of a 2019 presentation by Amy Shapiro MD, CEO and co-medical director of the Indiana Hemophilia & Thrombosis Center in Indianapolis, Indiana, USA, describing the rebalancing agent concizumab, approved as Alhemo® by Health Canada in March 2023 but rejected by the US FDA on May 5, 2023, with a request for […]

Bleeding Disorders

Fitusiran: A “Rebalancing Agent”

Fitusiran is an inhibitory double-stranded RNA (RNAi, also called small interfering RNA, siRNA). Fitusiran, termed a “rebalancing agent,” suppresses the nuclear production of antithrombin (AT) messenger RNA (mRNA). AT is a major coagulation control protein that binds and disables thrombin and FXa (also FIXa and FXIa to a lesser extent). By suppressing AT production, fitusiran […]

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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