Platelet Function Testing

February, 2023 Quick Question: VWF Activity Assays

Our February 2023 Quick Question, “What VWF activity assay do you use?” attracted 32 responses. Here are the results: Automated VWF:RCo: 12 [38%] VWF:RCo: 10 [31%] VWF:GP1bR: 3 [9%] VWF:GP 1bM: 4 [13%] VWF:Ab: 2 [6%] VWF:CB: 1 [3%] Although the aggregometer-based ristocetin cofactor activity assay [VWF:RCo] is criticized for poor reproducibility, with interassay CV […]

Bleeding Disorders

July 2022 QQ: Reduced concentration RIPA test.

Our July 2022 Quick Question asks, “What von Willebrand disease [VWD] subtype is identified using the reduced concentration ristocetin-induced platelet aggregometry [RIPA] test?” Many of the VWD types and subtypes are currently identified using molecular diagnosis, however, the “legacy” phenotypic tests often provide a speedy and inexpensive shortcut. This may be one such case. Please […]

Bleeding Disorders

ISTH Guidelines for Treatment of TTP

Reminder, in 2020, the International Society for Thrombosis and Hemostasis [ISTH} released their “ISTH Diagnosis Guidelines” and “ISTH TTP Treatment Guidelines.”Click here for access to the guidelines and their supporting material.”

Bleeding Disorders

February, 2022 QQ Response: Platelet Aggs

Thanks to our 57 FF participants for your responses to our February 2022 Quick Question. The question stem was: “What single agonist is your first choice to measure platelet response to aspirin?” ADP: 14% [8] TRAP: 2% [1] Collagen: 2% [1] Epinephrine: 28% [16] Arachidonic acid: 54% [31] Although this question is a poll, my […]

Arterial Thrombosis

Platelet-Cancer Cell Uptake

Here is an open-access original research report that illustrates cancer cells’ ability to uptake and mimic platelets, leading to access to the platelet proteome, implying that platelets may support metastases: /sites/default/files/plt-ca_cell_uptake_castanheira_jth_2021.pdf

Platelet Function Testing

VITT Mechanism Nature Preview

Here is a research article that was rushed to print in the July 7, 2021 Nature that describes the precise pathophysiology of vaccine-induced immune thrombotic thrombocytopenia [VITT]. VITT is the critical 1/60,000 incidence adverse event associated with the adenoviral vector employed in the Astra-Zeneca and Johnson and Johnson vaccines, among others. VITT resembles heparin-induced thrombocytopenia […]

Platelet Function Testing

More on Platelet Function Testing

From Dave McGlasson: George, Aquino in a recent article in CAP Today titled, “Puzzling out platelet function disorders,” posted July 6 on Fritsma Factor, extolled the virtues of light transmittance aggregometry [LTA] on platelet rich plasma [PRP] as the reference [“gold standard”] method to assess platelet aggregation disorders. This may have been true years ago […]

Platelet Function Testing

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

Scott Syndrome

I [Geo] provide a quarterly series of hemostasis lectures for UAB’s pathology residents and fellows. Last week, our transfusion medicine fellow, Richard Godby, MD, asked if I’d heard of “Scott syndrome.” This was new to me and also to two of my colleagues. Dr. Godby provided me with this Wikipedia link [click] that describes the […]

Platelet Function Testing

QQ Results: 5 YO Girl with Systemic Bleeding

Our January, 2020 Quick Question was based on our December 26, 2019 case, 5 YO Girl with Systemic Bleeding. This case generated discussion from experts around the world, whose comments are provided below. But first, here is the question and responses. Question: What diagnosis fits no aggregation reponse to ADP, collagen, and AA? The question […]

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