Bleeding Disorders

Platelet Function Testing

There is a comprehensive summary in the June, 2021 CAP Today by Amy Carpenter Aquino entitled, “Puzzling Out Platelet Function Disorders,” [click] featuring Catherine PM Hayward, MD, PhD, of McMaster University, champion of the time-honored light transmittance aggregometry [LTA} approach to platelet testing.

Bleeding Disorders

New Fundamentals in Hemostasis

Thanks to my colleague Carlo Ledesma, MS, SH(ASCP)QLS, MT(ASCPi), MT(AMT) for pointing me to an in-depth hemostasis review, Versteeg HH, Heemskerk JWM, Levi M, Reitsma PH. New Fundamentals in Hemostasis. Physiol Rev 2013;93:327–58. This is a valuable teaching resource that helps elucidate the cell-based hemostasis model.

Arterial Thrombosis

Acquired von Willebrand Syndrome [AVWS]

From Dr. Jasmina Aluwahlia, regarding detection of anti Von Willebrand factor antibodies. “Hello George, how does one screen for anti-VWF antibodies in a suspected case of acquired AVWS? We assay the VWF:Ag and VWF:GPIbR on a automated coagulometer. The VWF:GPIbR is based on a latex immunoassay. Is there any protocol that can be used on […]

Bleeding Disorders

Mixing Study Limits

From a participant: Can you please help me to understand how to make a cut off value for a correction study so that above this value is corrected and below is not? Please provide an example. Thank you. Hello, and thank you for your question. Please click this link to our educational module, “Improving Acute […]

Bleeding Disorders

Extended Half-life FVIII & FIX and the PTT

From Carolyn McCarville: Hi George, My small laboratory is trying to figure out the best management of coag samples from patients receiving extended half life factor replacement products. We understand that many of the one stage clotting factor assays are inaccurate for the wealth of these products. One thing that we cannot get a straight […]

Bleeding Disorders

March 2021 Quick Question Response

Our March, 2021 Quick Question was a case study that netted 49 votes. A 2 YO experiences frequent joint bleeds. PT: 22s; PTT: 29s; fibrinogen 280 mg/dL. What do you do next? Assay factors VIII, IX, and XI. 10% [5] Assay factors II, V, and X, 14% [7] Assay factor VII, 70% [34, correct] Assay […]

Bleeding Disorders

Testing for von Willebrand Disease Subtype 2N

I [Geo] ran across this 2011 Versiti protocol for identifying von Willebrand disease subtype 2N, “Normandy,” sometimes nicknamed “Autosomal Hemophilia A.” This is a sophisticated phenotypic method for finding the ratio of von Willebrand factor concentration [antigen] to coagulation factor VIII activity. Click here for their von Willebrand Disease Subtype 2N Protocol.

Bleeding Disorders

VWD Subtype 2N

Today a colleague asked, do the bleeding symptoms associated with von Willebrand disease subtype 2N [Normandy, “autosomal hemophilia”] disappear during pregnancy? Hoping for some answers from our clinical participants.

Bleeding Disorders

Quick Question March 2021: 2 YO W/ Anatomic Bleeds

Our March, 2021 Quick Question is a case study involving a 2 YO who experiences frequent anatomic [joint and body cavity] bleeds. The lab results are PT: 22s; PTT: 29s; fibrinogen 280 mg/dL. What do you do next? Please choose your anwer on the right. You will need to endure the “Captch” function, we’ve had […]

Bleeding Disorders

Quick Question Feb 2021: Easy Bruising Case

Our February, 2021 Quick Question was a case study that drew 60 responses. A 25-YO woman who is 1 month post-partum experiences bruising and menorrhagia. She reports that her mother and brother both experience easy bruising and that her own bruising disappeared during her pregnancy. What condition could cause these symptoms? Acquired hemophilia: 12% [7] […]

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.

Cheat Sheets from George

Quick Question