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Mixing Studies Procedure

George, I have just discovered your website while I was searching for articles on mixing studies. I am looking for an actual procedure on performing the mixing studies. Would you be able to refer me to a source for this? Thanks, Louise Schafer (Louise does not give her location) Hi, Louise. Thank you for your […]

Prothrombin Time Test Volume

Before we put up our next Quick Question, here are the results of the current question: What is your prothrombin time testing volume? a. 0-100/day: 19 (35%) b. 101-500/day: 29 (56%) c. 501-100/day: 4 (7%) d. Over 1000/day: 2 (4%) This illustrates the enormous volume of PT testing we perform, most, I assume, to monitor […]

VWF Assays and Hemolysis

Here are two new questions from Kim Kinney at Clarian in Indianapolis: We are validating VWF antigen and VWF activity (automated ristocetin cofactor) on our new TOP analyzer using the IL kits. One issue we see is that the kits are not very forgiving when it comes to hemolysis. Now, I know, hemolyzed samples are […]

The iSTAT Kaolin ACT

I have a provocative question about the activated clotting time (ACT) assay from my friend and one-time student Jeanine Walenga PhD, at Loyola University Medical Center in Maywood, IL. I don’t know a lot about iSTAT’s ACT so am posting this for general feedback. Dr. Walenga writes: We are validating the iSTAT kaolin ACT hospital-wide. […]

Critical Heparin Values

Dave McGlasson posted this question on Medlab_L and gave me his permission to paraphrase and copy it here: What do you use for critical heparin values when notifying providers about hemorrhage risk? It seems there is no standardization on this issue. Chest 2008;133, Antithrombotic and thrombolytic Therapy: American College of Chest Physicians Evidenced-Based Clinical Practice […]

Distinguishing Heparin Contamination from Therapeutic Heparin

Here is an interesting question from Dr Larry Smith at Memorial Sloan-Kettering: George, What is the consensus on how to handle samples drawn from a mediport that are obviously contaminated with heparin? We run a thrombin time to prove that they are contaminated, and request a peripheral draw. Sometimes we neutralize the heparin with a […]

Heparin-induced Thrombocytopenia with Thrombosis: The “HIT-Ache”

Presenter: Marisa B. Marques, MD Panelists: Dorothy Adcock-Funk, MD, Kandice Kottke-Marchant, MD, PhD, John D. Olson, MD, PhD Moderator: George A. Fritsma, MS MT (ASCP) Precision BioLogic Laboratory Medicine Roundtable, June 20 and 21, 2008, Dartmouth, Nova Scotia I’d like to thank Wendy Porteous, Steve Duff, Michael Scott, and all the Precision BioLogic Inc. participants […]

Quick Question: Critical INR Value Follow-up

In response to a question from Kim Kinney we posted the following “Quick Question” last week, “What is your critical INR call-out number?” The answers were relatively predictable… We call out at… INR 4.0: 10 (28.5%) INR 5.0: 20 (57%) INR 6.0: 3 (8.5 %) We don’t report a critical INR: 2 (6%) Total respondents: […]

Coordinating PT and PTT Results

Here is some follow-up to the question posted last week by Julie Schartiger MLT (ASCP) from Holzer Medical Center, Gallipolis, OH. Julie wrote: “I was wondering if there was a list of the specific disease states and the correction factors involved. For example, if a specimen was corrected by the addition of normal pooled plasma, […]

Interpreting Factor V Leiden Mutation and APCR Results

Good afternoon, I have been referred to you to ask about Factor V. After my sisters tested positive for this blood disorder I took the test for Factor V and was told that my count was 2.49. My family physician is not familiar with this disorder. I would like to know if this number means […]

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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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