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D-dimer Controls

In 2008, John Olson, MD provided a lengthy comment on the variabilities of D-dimer assay results, and since then a look-back reveals the number of discussions we’ve held about the variability in D-dimer reporting and how this affects clinical decision making. In the years since Dr. Olson’s post little has been accomplished to harmonize D-dimer […]

Quick Question Archive

QQ: VWF Activity

Here are the results of our January, 2018 Quick Question. Stem: What method do you use to measure von Willebrand factor activity? a. Ristocetin cofactor (VWF:RCo): 61% (32) b. Collagen binding assay (VWF:CB): 6% (3) c. VWF activity immunoassay (VWF:Act): 23% (12) d. Ristoectin-triggered recombinant GP 1b immunoassay (VWF:GPIbR): 4% (2) e. Non-ristocetin gain of […]

Bleeding Disorders

Xarelto Bleeding Intensity

George communicated with an acquaintance who experienced Coumadin therapy a few years ago and, subsequent to a new DVT, is now on Xarelto. He notes that minor cuts bleed longer and more profusely when on Xarelto compared to Coumadin. Can any of our subscribers confirm this?

Anticoagulant Therapy

Geometric V. Arithmetic Mean

From Dave McGlasson, does anyone have a reference on why a geometric mean is used in the INR calculation? Since we are using 20–30 normal subjects to calculate the mean PT, the range is relatively narrow. The geometric mean indicates the central tendency or typical value of a set of numbers by using the product of […]

Anticoagulant Therapy

Factor IX Assay News Release

George has attached a Precision BioLogic Inc. news release describing the outcomes of factor IX assay studies conducted with Sobi. The data were published in poster format at 11th Annual Congress of the European Association for Haemophilia and Allied Disorders (EAHAD). Thanks to Elaine Benoit, Precision BioLogic for the heads-up, and to Ali Sadeghi-Khomami PhD […]

Bleeding Disorders

January, 2018 Quick Question: RIs

Here are the results of our January, 2018 Quick Question, How do you establish a coag factor reference interval? A. Use a published RI from an article or textbook: 3 votes, 7% B. Validate manufacturer’s RI using ~ 20 locally collected aliquots: 16 votes, 39% C. Validate manufacturer’s RI using ~30 locally collected aliquots: 11 […]

Quick Question Archive

World Federation of Hemophilia

Thanks to Elaine Benoit, Precision BioLogic Inc, for the heads-up on this announcement. Geo. The World Federation of Hemophilia (WFH) is pleased to announce that the World Bleeding Disorders Registry (WBDR) will GO LIVE on January 26, 2018. This date will mark the first patient enrolled in the registry – which leaves just 9,999 more […]

Effect of Fibrinogen on PT and PTT

From Alan Neal, Pathlab, NZ. Just wanted a private conversation about the January 11, 2018 Fritsma Factor entry, “POC and Plasma-Based PT/INRs.” I do not agree with the comments made within this article and challenge the logic used. Essentially, if monitoring an enzymatic pathway such as coagulation, with the ‘detector’ being used is fibrinogen to […]

Global Hemostasis Assays

Fritsma Factor Calendar

We’ve recently updated our Conferences Calendar. If you would like your conference to be listed, please contact George at [email protected].

ISTH SSC Abstracts Due Feb 1

The International Society on Thrombosis and Haemostasis annual SSC meeting is July 18–21, 2018, in Dublin. Delegates who would like to present their work at the meeting, either orally or as a poster, are invited to submit an abstract for consideration by the Scientific Committee. There are no fees to submit, and the submission deadline is Thursday, […]

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George Fritsma is a medical laboratory scientist, educator, and author. George is a member of the International Society on Thrombosis and Hemostasis, the International Society for Laboratory Hematology, and the American Society for Clinical Laboratory Science.

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