Bleeding Disorders

More on Nijmegen-Bethesda Test Volumes

From Ali Sadeghi-Khomami PhD, Precision BioLogic scientist. Access to national and global testing databases is needed to answer the NBA test order volumes question. I am unsure if such a database exists, but relevant data could also be retrieved from insurance companies to estimate the annual rate of NBA inhibitor assays. Yearly marketing report documents […]

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

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.

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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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