Quick Question Archive

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

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

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

July 2024 Quick Question: Specimen Storage

Our July 2024 Quick Question, which drew 58 responses, asked, “How long may you store a specimen after collection for a PT test?” Our answers were: 1 hr: 2 (3%) 4 hrs: 19 (33%) 8 hrs: 7 (12%) 24 hrs: 30 (52%, the correct answer) This question draws attention to the March 2024 publication of […]

Quick Question Archive

July 2024 QQ: Specimen Storage

Coag specimen mismanagement is the source of most errors in hemostasis testing. As mentioned in our June 28, 2024 entry, Adjusting AC Volume in Polycythemia, CLSI released its latest edition of H21: Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based Coagulation Assays, 6th ed. Guideline H21, Clinical Laboratory and Standards Institute, 2024. The […]

Specimen Management

June 2024 QQ Poll Summary: OSA and Chromogenics

Our June 2024 Quick Question attracted 18 responses. This month’s Question was a poll that asked, “How do you assay factor concentrates?” Here are our answers: Clot-based assay: 11 [61%] Chromogenic substrate assay: 4 [22%] Other: 3 [17%] Factor assays are most often requested to monitor hemophilia factor concentrate activity for patient-specific efficacy and the […]

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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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