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Underfilled or Overfilled Coagulation Specimen Tubes

The CLSI H21 standard lists causes for coagulation specimen rejection, including hemolysis, icterus, lipemia, clotted specimens, underfilled tubes, and overfilled tubes. In most applications, underfilling is defined as a specimen comprising less than 90% of the stated volume. Most blue-closure tubes contain 0.3 mL of 3.2% sodium citrate and are calibrated to collect 2.7 mL […]

Specimen Management

Anticoagulation in Thrombocytopenia: Case Study

Here’s a composite case study. A 70-year-old male was treated for colon cancer and is in remission. Complications include congestive heart failure, esophageal varices, and recently diagnosed NVAF. Subsequent to chemotherapy, his platelet count has remained stable at 20–30,000/uL (RI 150–450/uL) and he experiences easy bruising. What assay would you recommend to enhance the safety […]

Bleeding Disorders

Chromogenic FX Assay versus PT/INR

Here is an April 1, 2025, “Differential Discussions” webinar hosted by Malissa Norfolk, University of Maine Augusta, and David Cabral, University of Massachusetts Dartmouth. It features my colleague David McGlasson on the subject of “Comparison of the CFX Assay to the INR for Monitoring OAC Therapy.” Thank you to these three hemostasis experts for this […]

Anticoagulant Therapy

Fitusiran Approved March 28, 2025

Thanks to Ali Sadeghi-Khomami, PhD, PBI research scientist, for the following heads-up: On Friday, March 28, 2025, Sanofi Inc. announced the much-awaited approval of fitusiran (Qfitlia®), a “rebalancing” therapeutic that dramatically reduces the ABR in hemophilia A and hemophilia B patients ≥12 YOA with or without inhibitors. Fitusiran is a messenger RNA inhibitor (RNAi) that […]

Bleeding Disorders

Lab Developed Tests Rule

Thanks to PBI’s Dean Willett for his heads-up about the March 31, 2025 ruling, “FDA‘s LDT Rule Struck Down in Texas Court.” The US FDA‘s 2024 “Final Rule” outlined plans to subject lab-developed tests to the same requirements as medical devices. The Texas ruling illustrates the US struggle to achieve a realistic approach to validation […]

April 2025 Cheat Sheet

Click here for your April 2025 Fritsma Factor Cheat Sheet listing all our March 2025 entries. Your personal Cheat Sheet will arrive in your email mailbox by April 7,2025. If you’d like to join the Cheat Sheet mailing list, navigate to the Cheat Sheet Signup function at the right on our “Posts” page. Thank you […]

April 2025 Quick Question: How to Measure Warfarin in a LAC Patient

Our April 2025 Quick Question is a poll that asks, “How do you measure warfarin in a patient with lupus anticoagulant (LAC)?” This question is a sequel to our March 2025 question, “How do you test for lupus anticoagulant?” that references the ISTH‘s most recent LAC guidelines, Devreese KMJ, Bertolaccini ML, Branch DW, et al. […]

Lupus Anticoagulant

March 2025 Quick Question: LAC Testing Outcome

Our March 2025 Quick Question asked, “How do you test for lupus anticoagulant?” The question drew 38 responses. DRVVT Screen/Confirm only: 4 (11%) PTT Screen/Confirm only: 2 (5%) First DRVVT S/C then PTT S/C if pos: 1 (3%) First PTT S/C then DRVVT S/C if pos: 3 (7%) Both DRVVT S/C & PTT S/C: 27 […]

Lupus Anticoagulant

Caplacizumab Immune-mediated TTP Clinical Efficacy Report

Thanks to colleague X. Long Zheng, MD, for his LinkedIn heads-up announcing the 31 March 2025 eClinicalMedicine release of Caplacizumab use in immune-mediated thrombotic thrombocytopenic purpura: an international multicentre retrospective Cohort study (The Capla 1000+ project). This pivotal open-access article compares patient mortality rate and the response rate to caplacizumab (Cablivi®) to standard care.

How to Improve Lab Testing

From Heather DeVries: In the scope of the whole world, how do labs search for new ways to improve their laboratory testing? Would it just be typing in the search bar, or are there ways to find the latest information randomly while looking for other things? George replies, Heather, my surface-level response is to suggest […]

Specimen Management

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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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