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VWD in Nigeria: Request for Proposal

Hello George. I am reaching out from my research institute as we are planning to apply for a grant from the Wellcome Trust. Our project title is “Comprehensive Characterization Of von Willebrand’s Disease in Nigeria; Closing the Gap in Global Bleeding Disorders.” As a collaborator, you will be asked to support the delivery of the […]

Bleeding Disorders

Prolonged DRVVT Screen

Soha Abuelela asked how to report a DRVVT screen above 120 seconds and how to report the ratio. I [Geo] consulted with my colleague Dave McGlasson. We began by assuming that 120 seconds represents your instrument’s limit and that the actual clotting time was unrecorded. It could be that your specimen has an undetected clot […]

Anticoagulant Therapy

VKA Monitoring in Hepatic Insufficiency

Here is a challenging case from Hrvoje Melinšćak sent 5-30-24: Dear George, In hepatic insufficiency there is often a prolonged basal protime, how to ensure therapeutic values of warfarin when the INR is already elevated? This is of particular concern in those with mechanical cardiac valves. Serum warfarin levels (spectrophotometry) are cumbersome and take days to […]

June 2024 Cheat Sheet

Here’s your June 2024 Cheat Sheet. Watch for your copy in an upcoming email blast.

June 2024 QQ: Factor Assays

Our June 2025 Quick Question is a poll that asks, “How do you assay factor concentrates?” The question reflects the current hemostasis laboratory efforts to quantify therapeutic FVIII or FIX concentrate activity given the variety of plasma-based, recombinant, B-domain-deleted, and extended half-life therapeutics. We also manage factor concentrates that are employed to control breakthrough bleeds […]

Quick Question Archive

May 2024 QQ Summary: Platelet Transfusion Trigger

Our May 2024 Quick Question was a survey that asked, “Below what PLT count limit do you provide PLT concentrate?” our 25 participants answered as follows: <150,000/uL: 2 [8%] <50,000/uL: 3 [12%] <20,000/uL: 7 [28%] <10,000/uL: 13 [52%] <5,000/uL: 0 The correct answer is “it depends.” Current WHO platelet concentrate transfusion guidelines are available at […]

Quick Question Archive

Marstacimab Anti-TFPI Moab Submitted for FDA and EMA Approval

Pfizer has applied to the US FDA and the European Medicines Agency [EMA] for approval of their monoclonal antibody anti-tissue factor pathway inhibitor [TFPI] therapeutic, marsticimab, a competitor to Novo Nordisk’s concizumab, approved by Health Canada under the trademark Alhemo®, and awaiting FDA and EMA approval. The FDA anticipates an FDA ruling in the fourth […]

Bleeding Disorders

Clot Detection by Wooden Sticks

Fritsma Factor participants, a colleague brought up the problem of clotted hemostasis specimens within the context of remote specimen collection. Many facilities recommend checking whole blood specimens with wooden sticks, a policy that has been in place since before 1990 but raises concern for contamination, clot activation, and operator safety. The broad availability of automation […]

Specimen Management

PBI Webinar: FVIII & FIX Testing of Emerging Therapies

I (Geo) recommend a May 8, 2024 Precision BioLogic webinar by Chief Scientific Officer Jon Geske, PhD and Marketing Director Ian Burns that compares one-stage clot-based and chromogenic assays when testing for the activity of extended half-life FVIII and FIX concentrates, FVIII mimetics such as emicizumab, RNAi’s such as fitusiran, and the products of FVIII […]

Bleeding Disorders

Is DRVVT Normalization Necessary?

The clot-based dilute Russell viper venom test (DRVVT) reagent activates the coagulation mechanism’s common pathway at the factor X (10) level, relying only on factor V, prothrombin, and fibrinogen for clot formation. The DRVVT test complements the PTT-based assay for lupus anticoagulant (LAC) detection. Because LAC is phospholipid (PL)-dependent, both assays use a minimal-phospholipid (PL) […]

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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

Quick Question