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Von Willebrand Factor Reference Ranges

Some von Willebrand questions from “Charlie” in Edmonton: What are the reference ranges for von Willebrand factor (VWF) antigen and for factor VIII? And what might cause these values to increase in a person who was originally thought to have a problem with being able to clot? Hi, Charlie. the typical reference ranges for VWF […]

Factor IX Deficiency in a 2-month Old

An interesting case sent by Sue Hollister: Hi George, We recently had an interesting case of a 2-month old who presented with a brain bleed. His PTT was 53 seconds and his factor VIII was normal, but his factor IX was 4%. Looks like a pretty simple case of hemophilia B, however, after treatment with […]

More on the Trinity Biotech KC1 from an Educator

Here is a recent comment from my friend and colleague, Dan Southern, Professor Emeritus, Western Carolina University: Hey, George, I read the piece that Kevin McGlinchey wrote for your blog. I have dealt with Kevin and he is very easy to work with. He understands the restraints of academe and realizes the future is our […]

Lupus Anticoagulant and Hex-phase Phospholipid Reagent

Here is a question from “Yellis” at Mayo Labs: George, I am new to this website. I discovered it through an article in the recent MLO. Do you know the particulars about the hexagonal phase confirmation testing done as a reflex for positive lupus anticoagulant (LA) results? How is it performed? I am not familiar with it and our […]

Baseline PTT for Heparin Therapy

A question from Joe Lamb: Hi George, I’m sure this never happens at other institutions, but occasionally here a patient is started on heparin therapy before a baseline PTT specimen is collected. Could you collect a specimen, absorb with heparinase and use it for the baseline PTT time? Hi, Joe, This is a great question, […]

Hold PT Specimens for Up To 24 Hours

Here’s a note from T. Spratley: We have protime specimens delivered from offsites that are older than 4 hours. Are they acceptable? I know some places accept them up to 24 hours old. Hi, T. Spratley. Thank you for your question. Yes, in accordance with CLSI Guideline H21-A5, “Specimens for PT assays uncentrifuged or centrifuged […]

More on Trinity’s KC1 and KC4 Educational Promotion

Here is a message from Kevin McGlinchey, Trinity Biotech, recommending his KC1 and KC4 instruments for teaching tools and describing Trinity’s special promotion for Medical Laboratory Science schools. George, Greetings! We would truly appreciate any and all help in getting the word out about the wonderful advantages of using our KC1 instruments for coagulation student training classes. […]

Trinity Biotech’s KC1 and KC4 for Educators

Here is a comment from Dr. Lynne Williams of Oakland University, Oakland, MI that was originally posted to the CLSEDUC list about Trinity Biotech’s desktop instrument, the KC1. “We use the KC1 in our Hemostasis class. They are a great (and less expensive) alternative to fibrometers. They are manufactured by Trinity Biotech (Amelung), and for the past two years, […]

Lupus Anticoagulant and Factor XI

Here is a message from Carol Houde of Emerson Hospital: I’m interested in the association between elevated factor XI activity and the lupus anticoagulant. When doing dilutions how do you effectively differentiate between the “lupus effect” on this PTT-based assay (especially when the LA result is borderline positive)? Hi, Carol. Sorry to say, I know […]

Prekallikrein Assay

A question from Delphine in France about prekallikrein (PK, Fletcher factor) deficiency measurement: is there a difference between the PTT with kaolin versus silica to measure PK deficiency? What is the impact of incubation time? It seems PTT with kaolin doesn’t work well to measure PK? Hi, Delphine. I checked your question with Lynn Quarles […]

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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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