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Mixing Studies and the Rosner Index

Here is a 2-12-2024 message from Brenda Goforth, Senior CLS Hematology, Coagulation, and Urinalysis; Clinical Laboratory Antelope Valley Medical Center, Lancaster, CA 93534. Hello, I would like some clarification on the subject of mixing studies using the Rosner Index cutoff compared to the “>10% of the normal pooled plasma [NPP] limit” in regards to incubation […]

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

CAP Today: Thrombophilia Testing

Here is a January 2024 CAP Today summary of current thoughts about The Who, When, and Why of Thrombophilia Testing.

Interpreting Inhibitor Mixing Study in a Hemophilia A Patient

I [Geo] received a physician’s question on 1-31-24: Dear Sir, Hope you are doing well. Thank you for creating this platform and sharing valuable resources with the world. We present a case of Hemophilia A with recent retroperitoneal hematoma and multiple transfusions–PRBC, FFP, Factor VIII, and NovoSeven. APTT of Test Plasma: 47 seconds [RI 22.2–33.1 […]

More on Chronically Elevated D-dimer

I [Geo] received this 2-1-24 email from a correspondent who had expressed concern for his isolated elevated D-dimer. This is an issue we’ve addressed in the past that prompted me to prepare a summary entitled Isolated Chronically Elevated D-dimer. Here’s the note: Hello. We had email contact in 2023 and it was about a chronically […]

February 2024 Cheat Sheet

Hello, here is your February 2024 Cheat Sheet. Watch for yours in your email next week. Thanks for your continued participation in Fritsma Factor.

Feb 2024 Quick Question: Rosenthal Syndrome

Our February 2024 Quick Question is a quiz that tests the knowledge we gained in our entry-level coagulation courses. At the end of February, we’ll use this as a means to discuss the efficacy of currently available DOACs and some new developments.

Coagulation Factors

January 2024 Quick Question Response: Platelet Function Tests

Fritsma Factor’s January 2024 Quick Question asks, “What platelet function test do you use?” Our 43 participants responded… Light transmittance aggregometry: 15 [35%] Whole blood aggregometry: 7 [16%] Lumiaggregometry: 8 [19%] Bleeding time: 0 PFA 100/200: 13 [30%] Presuming that those who chose the lumiaggregometry entry perform theirs on an impedance-based whole blood aggregometer, we […]

Quick Question Archive

Anti-XI Anticoagulant

Here is a transcript of an interview with Christian T. Ruff, MD, Senior Investigator, Thrombolysis in Myocardial Infarction (TIMI) Study Group, Boston, Massachusetts,USA describing the favorable AZALEA-TIMI Phase 2 safety study of a monoclonal anti-XI once-a-month injectable anti-XI anticoagulant, abelacimab.

Anticoagulant Therapy

Please Provide Comments: Prolonged PT and PTT, Retinal Bleed

I’m [Geo] seeking comments about this case of a 65-YOA female on no anticoagulant with retinal hemorrhage and no other bleeding symptoms: Coag 1/18/24 1/19/24 1/20/24 1/21/24 PT 16.9 15.6 PTT 53 44 TCT 17 FG 592 576 FII 83 FV 79 FVIII 167 FIX 71 FX 75 FXI 80 VWF:Ag 121 VWF:RCo 147 D-dimer […]

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