Bleeding Disorders

December 2020 Quick Question: Emicizumab

Our December, 2020 Quick Question addresses the uncommon incidence of breakthrough bleeds in hemophilia A patient who are being treated with emicizumab [HEMLIBRA], the immunotherapeutic that bypasses factor VIII. Treatment may become an issue in severe hemophilia in which patients develop inhibitors. See our November 29 post, Emicizumab Laboratory Assay Review [click] for some hints […]

Bleeding Disorders

November 2020 QQ: VWF Activity Assay Responses

Our November, 2020 Quick Question attracted 37 participants. Here is the stem: “Which VWF activity assay is preferred at your facility [check 10-31-20 post]?” The selections were… VWF:RCo: 58% [21] VWF:GP1bR: 3% [1] VWF:GP1gM: 14% [5] VWF:Ab: 3% [1] VWF:CBA: 22% [8]* The time-honored Ristocetin cofactor assay remains the most prevalent of VWF activity assays. […]

Bleeding Disorders

Emicizumab Laboratory Assay Review

Here is a comprehensive review of the 2017 hemophilia A therapeutic emicizumab [HEMLIBRA]. The author, Michael A. Nardi, MD, NYU Langone Health, details the effects of emicizumab on standard clot-based laboratory assays and the need for chromogenic substrate test methods. Click Nardi MA. Emicizumab and the clinical laboratory. Clin Lab Sci 2017; 30.DOI: https://doi.org/10.29074/ascls.119.002204.

Bleeding Disorders

November 2020 Quick Question: VWF Activity Assay

Our November, 2020 Quick Question asks, what von Willebrand factor activity assay is being used in your facility? Click here for the ISTH summary: Bodo I, Eikenboom J, Montgomery R, et al. Platelet-dependent von Willebrand factor activity. Nomenclature and methodology: communication from the SSC of the ISTH. J Thromb Haemost. 2015; 13:1345–50. doi:10.1111/jth.12964; or click […]

Bleeding Disorders

Factor IX Assay Unexpected Results

Mike Meyer asks, “we run three dilutions for all of our factor testing. Occasionally, we see results in which upon higher dilutions, the factor value decreases after adjusting for the dilution. For instance, I had a case today in which the FIX values were 0.64, 0.55, and 0.43 U/mL for the 1:10, 1:20, and 1:40 […]

Bleeding Disorders

Mixing Studies

A note from colleague Kathy Robinson that deserves a thorough discussion… “I am updating our mixing study procedure and have some questions…” 1. What is the lower limit at which it is useless to perform studies for both PT & PTT [APTT]? There is no firm agreement about the limit. Some perform mixes whenever the […]

Bleeding Disorders

WFH Guidelines: Third Edition

On August 4, 2020 the World Federation of Hemophilia announced the publication of the WFH Guidelines for the Management of Hemophilia, 3rd edition, 2020 [click for the publication]. The guidelines were developed by a team of experts from around the world and have been updated to reflect important developments in the management of hemophilia since […]

Bleeding Disorders

Chromogenic Factor VIII Assay FDA-Cleared

On Monday, July 20, Fritsma Factor sponsor Precision BioLogic Inc. announced US FDA 510[k] clearance of their CRYOcheck™ Chromogenic Factor VIII assay. The assay had been previously approved in Canada, the European Union, Australia, and New Zealand. The assay boasts a test range from 0–200% FVIII using one standard curve and a limit of quantitation […]

Bleeding Disorders

April, 2020 Quick Question: HEMLIBRA Results

Our April, 2020 Quick Question was: “How does your facility measure factor VIII during HEMLIBRA therapy?” Here are our answers from 29 respondents: a. One-stage PTT-based FVIII assay: 17% (5) b. Two-stage chromogenic FVIII assay: 45% (13) c. PTT-based assay calibrated to emicizumab: 10% (3) d. There is no reliable assay: 28% (8) Dr. Ali […]

Bleeding Disorders

World Hemophilia Day

Today, April 23, 2020 is World Hemophilia Day. Click or tap here and visit the World Federation of Hemophilia site, where you find in-depth information and a webinar featuring care for hemophiliacs in the face of Covid-19. Our sponsor, Precision BioLogic Inc. is an annual WHD sponsor.

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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