Bleeding Disorders

Hemophilia: Bispecific Antibody

Here is an editorial that appeared in the December, 2016 Journal of Thrombosis and Haemostasis describing the thinking that led to a coagulation factor VIII mimetic. This is a bispecific antibody that approximates factors IX and X to activate X while bypassing factor VIII. Designated ACE910, the mimetic enables normal clotting in hemophilia A when […]

Bleeding Disorders

Chromogenic VIII and IX Assays

What are the most accurate and reproducible assays for factors VIII and IX. For answers, I recommend an excellent educational article, Adcock D, Pruthi R, Tiefenbacher S, The value of the chromogenic activity assay in diagnosis and therapeutic monitoring of hemophilia. Med Lab Observer 2017, February, 8–14.

Bleeding Disorders

Acquired Glanzmann

Dr. Sarode’s February 17 post mentioned acquired Glanzmann thrombasthenia (GT). I’ve attached a case study describing and defining this autoimmune bleeding disorder. By coincidence, Heather DeVries saw an acquired GT in the Indiana University Medical Center lab. Heather used her own platelets as a control to demonstrate how the patient’s antibody suppressed normal platelet aggregation. […]

Bleeding Disorders

Platelet Clumps in Citrate Tube

Dear Fritsma Factor, I am a hematopathology fellow evaluating the following patient for thrombocytopenia. History and laboratory results are listed in detail below. We have encountered a situation where the patient develops platelet clumps within citrate tubes but not in EDTA. I have found only limited information regarding this phenomenon and was wondering if anyone […]

Bleeding Disorders

Whole Blood PTTs

From Kirk Guyer, Cascade Technologies: There are whole blood PTT (APTT) assays and there are citrated platelet poor plasma (PPP) PTT assays. What happens in a PPP PTT assay if there are platelets present? Does the PTT result shorten? Can platelets shorten the PTT result in a whole blood PTT assay? I ran a PTT […]

Bleeding Disorders

Bleeding Time Efficacy

From George’s Birmingham colleague, Vicki Cardone: We are trying to discontinue bleeding times! I have spoken to Helena PlateletWorks about their method and they said it will not pick up VWD or Glanzmann thrombasthenia. Do you know of anything to replace BT? We don’t want to use PFA. Thank you, Vicki. Hi, Vicki. I encourage […]

Bleeding Disorders

Intermittent Bleeding, Normal Coags

From Dr. Samir Patel: George, I was wondering if I could get some input from you or any of the other readers regarding a patient in my clinic. This is a 52 year old woman with history of multiple surgeries (dental, orthopedic) and with mixed history of intraoperative bleeding, late bleeding, and no bleeding. She […]

Bleeding Disorders

Quick Question Results: Bethesda Titers

The results of our latest Quick Question are in with 87 responses.. How does your laboratory measure factor inhibitors? Standard Bethesda assay: 33% (26) Bethesda titer using buffered pH 7.4 pooled normal plasma: 9% (8) Nijmegen Bethesda assay using factor-depelted plasma as diluent: 9% (8) CDC modification of Nimegen Bethesda assay: 0% (0) Bethesda chromogenic […]

Bleeding Disorders

Chilling The NBA Reaction Mixture

From Dr. Mirta Arias: Dear George, Thank you for your answer in the blog. I have another question. Dr. Robinson in ISLH argued that it is good to chill the post 2 hour/37°C 37 incubation mixtures of patient + pool normal plasma, and control at 2–8°C for 10 minutes and then measure the factor VIII. In […]

Bleeding Disorders

Nijmegen Bethesda Assay

From Dr. Mirta Arias, Dear George, which is the procedure for determining the cut-off of Bethesda method and Nijmegen? Is there any Excel spreadsheet to perform it? Do you use only normal or normal and patients? Thanks, Mirta Hello, Dr. Arias, and thank you for your question. For a comprehensive answer, I turned to Amanda […]

Bleeding Disorders

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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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