Screening Assays

September 2024 Quick Question Response: PTT and FVIII Level

Our September 2024 Quick Question drew 59 responses and asked: “At what FVIII activity level should the PTT become prolonged?” Our answers were: 60 U/dL: 6 (10%) 40 U/dL: 37 (63%) 10 U/dL: 12 (20%) 1 U/dL: 4 (7%) Most of us chose the correct answer. The PTT “partial thromboplastin” manufacturers develop their reagent to […]

Bleeding Disorders

September 2024 Quick Question: PTT

I (Geo) prefer PTT to APTT or aPTT because the “A” or “a” is superfluous. Laboratory scientists no longer offer an “unactivated” PTT. The “partial thromboplastin” reagent consists of a phospholipid or combination of phospholipids that may include animal, plant, or synthetic sourced phosphatidylserine, phosphatidylcholine, phosphatidylinositol, sphingomyelin, and/or phosphatidylethanolamine. Accompanying the phospholipid is one of […]

Lot Conversion for CaCl2?

From Cynthia Hollis on 2-2-24: I had someone ask me why I didn’t do a lot conversion for changing lots of CaCl2 that I use in my APTT assays. I was unable to give them a satisfactory answer. Can you explain it for me, please? From Geo: Hi, Cynthia, thanks for your question. I checked […]

Screening Assays

November 2023 Quick Question: Platelet Hyperaggregability Summary

Our modest 15-player response to the November 2023 Quick Question poll implies a scant interest in platelet hyperaggregability, the outcome of an October 4 post by Mayukh Sarkar, PhD. “Sticky Platelet Syndrome.” Question: Do you test for platelet hyperaggregation? No, there’s no such thing: 6 [40%] Yes, we call it “sticky platelets:” 6 [40%] We […]

Arterial Thrombosis

CAP Today Announces VEA Guide

The October 2023 issue of CAP Today announced the publication of Volod, O, Whole Blood Viscoelastic Assays in Clinical Diagnosis: An Illustrated Case-Based Guide. A brief interview with editor Oksona Volod, MD, describes the guide and lists its contributors. The guide is a comprehensive review of whole blood viscoelastometry [VET] from its start with the […]

Global Hemostasis Assays

CLN: Viscoelastometry Article

Here is a May 2023 Clinical Laboratory News cover review by colleague and fellow “clotter” Oksana Volod, MD, entitled “Is TEG the Right Assay? [click]” The article describes the updated means for near-patient viscoelastometry assays, whose original methodology became available in 1948. Clinical Laboratory News is a widely distributed American Association for Clinical Chemistry [AACC} […]

Global Hemostasis Assays

Discrepant PT and INR Results

From Soha Abuelela. I’m using the ACL Pro Elite for PT and PTT testing in my lab using Hemosil Recombiplastin 2G reagent but I frequently notice sample results showing normal PT time in seconds with normal concentration but the INR is above the reference interval! Could you please help me with possible causes and your […]

Anticoagulant Therapy

December, 2022 Quick Question: Thrombosis Risk Profiles

I’ve been reviewing Choosing Wisely recommendations and Medscape discussions on the importance of assays for congenital thrombosis risk factors such as antithrombin, protein S, and protein C. We’d like to know what comprises our profiles by asking “What parameter is NOT part of your thrombosis risk factor profile?” Please access our December Quick Question on […]

Quick Question Archive

Hemolysis Level and Coag Assays

A timely question from Frank Cragg, MD, Nova Scotia Health. “Hi, I have the IL 750 ready to implement but am getting conflicting information on how much hemolysis to allow. Please help. Regards, Frank Cragg MD, FRCPC [C]. Hello, Dr. Cragg, and thank you for your question, which I’ve forwarded to several experts. Although more […]

Screening Assays

November 2021 Quick Question: Case Study, Prolonged PTT

Our November 2021 Quick Question involves a 3-year-old female patient with no bleeding history whose pre-op PT and PTT results were PT 13.3 seconds [RI 12-6–14.6] and PTT 51 seconds [RI 25–35] and asks what is the most likely coagulation factor deficiency. Please select your answer and add your comments below.

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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