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Factor Levels in Hemophilia

Mary Paoli of Palmetto Health asks, “When hemophilia is classified as severe, moderate or mild, are factor VIII activity levels (FVIII:C), reported in percentage, or factor VIII antigen (FVII:Ag), reported in U/dL? Thank you for your question, Mary. When a newborn boy is at risk of hemophilia, his plasma is tested using the plasma-based factor […]

Monitoring von Willebrand Disease Therapy

Eight participants answered our June 16-21 hemostasis question asking how we monitor von Willebrand disease therapy. Three employ the von Willebrand ristocetin cofactor assay (VWF:RCo, VWF activity). This is the method recommended by the Scientific Sub-Committee on von Willebrand Factor of the International Society of Thrombosis and Haemostasis (ISTH-SSC on VWF). However, four prefer the […]

Von Willebrand Disease Therapy

On June 1 I provided two hemostasis lectures for Dr. Ingrid Oakley’s Nurse Anesthesia course at the University of Alabama at Birmingham. I particularly like doing these lectures because I admire and respect Dr. Oakley; UAB’s remote online real-time technology is cool, and the students are serious, bright, and engaging. These are experienced nurses working […]

Does Hemolysis Affect the Anti-Xa?

Here is another question from my friend and colleague, Vicki Cardone, Hematology Supervisor at Children’s Hospital of Alabama, just across the street from my own University of Alabama Hospital: Would a hemolyzed sample cause the anti-Xa value to be falsely decreased as it would give a stronger color reaction, or am I just way off? […]

Quick Question: Heparin Detection

Eleven of our over 300 subscribers participated in last week’s quick question, which was: “How does your laboratory detect unrecorded heparin in a plasma specimen?” Here are the answers: Eight (73%) use the thrombin clotting time, two just treat the specimen with hepzyme, and one uses the anti-Xa heparin assay. It looks like no one […]

More on Cranberry Juice

From Cynthia McKenzie, RN: Many years ago I knew of a patient who was stable on Coumadin. A PT/INR was drawn on a Thursday and it was therapeutic. On Friday evening she complained of nausea and requested cranberry juice. A 1/2 to 1 gallon container was brought in by a family member. She refused food […]

Von Willebrand Disease: Collagen Binding Assay

Here is a June 6, 2008 message from Kim Kinney at Clarian in Indianapolis: Hi George, We are going to evaluate a kit for collagen binding. I remember at the Midwest Symposium this year Dr. Adcock commented on the type of collagen used in the kit and that one was better than another. From what […]

Nurse Anesthesia: VWF Dosage Calculation

Here is an example of how to calculate the dosage of von Willebrand factor (VWF) for a patient with severe von Willebrand disease (VWD). The preparation used most in the US for VWF replacement is Humate P, a fractionated human plasma product rich in VWF. The computation example may also be applied to replacement factor […]

Weekly Survey Question

A new Fritsma Factor survey feature appears in the right margin in the form of a multiple-choice question. Please select and click on your answer. We’ll compile your answers and publish the composite on the following Monday, the same day a new question is posted. If you would like to make an additional comment clarifying […]

Nurse Anesthesia Question: Thrombin Clotting Time

On Monday, June 2, I provided two 90-minute lectures for Dr. Ingrid Oakley’s graduate Nurse Anesthesia Program students at the University of Alabama at Birmingham (UAB). The first lecture was “Hemostasis Overview and Managing the Bleeding Patient,” and the second was “Thrombophilia and Managing Antithrombotic Therapy.” It is tough on students to attempt to cover […]

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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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