All Posts

Switching From Rivaroxaban to Heparin

Amy Kelley, Dahl Chase Diagnostic Services, asks, one of our hospitals had a patient on Xarelto who came in for surgery. This hospital uses STAGO Xa testing which uses a hybrid curve. The patient’s Xa should drop after 3 days. The patient was put on unfractionated heparin (UFH) while in the hospital. Our question: Should […]

Anticoagulant Therapy

Mixing Study Correction Limits

Dr. Tony Tang asks, In a mixing study, how many seconds difference between the APTT of the test plasma+normal plasma (NP) incubated after mixing together, and the APTT of the test plasma and NP incubated separately before mixing, can suggest a positive result for factor VIII inhibitor? Are there any references? Thank you! Hello, Dr. […]

Subjects in Reference Interval Study

Mona Murphy, Pathology Laboratory, Lewiston, ME reports using 20 males and 20 females in a normal range study.

Quick Question Archive

Validations Using Commercial Plasmas

Chris Powell at King’s Daughters’ Health asks: commercial plasma distributors offer pre-screened patient specimens for PT and PTT lot rollover. How can this product be used and still meet the CAP and CLIA requirement to collect specimens from your own patient population? Hi, Chris, thank you for your question. I’ve modified your reference to a […]

Trauma-induced Coagulopathy Presentation

Thanks to Melissa Doumolin, Sonja Nehr-Kanet, and everyone in Boise who made my visit to Idaho memorable. Thanks also to those who participated in the presentation, “Trauma-induced Coagulopathy and Massive Transfusion Protocol.” I’ve attached my handouts in 1-per-page and 6-per-page format; the former if you want to see it on your phone or tablet, the […]

Bleeding Disorders

Lab Week 2016

Please join George and the professionals at Precision BioLogic Inc. as we celebrate Medical Laboratory Professionals Week (“Lab Week“), April 24–30, 2016. By way of celebration, Precision BioLogic will sponsor a free webinar, Identifying, Measuring, and Treating Coagulation Factor Inhibitors, presented by George Fritsma, on Thursday, June 2, 2016 at 1 PM EDT. Please select […]

Factor V Antigen Assay?

From Heather DeVries, Indiana University. Hello George! We have a physician requesting a factor V antigen assay. I have not been able to find it anywhere. Do you know if there is an assay for this? If so, who performs it? Thanks! Heather. Hi, Heather. I checked the usual specialty reference labs and the companies […]

Bleeding Disorders

PT and INR Means

Wendy Sutula at Medstar asks about the PT reference interval calculation. Hi, George. Each time we convert to a new lot of PT reagent we run normals and calculate a geometric mean (geomean) to be used in the INR calculation. My question is this. When we are validating or re-validating the PT normal range, is […]

Anticoagulant Therapy

Xarelto and D-dimer

George and Dr. Louann Lawrence have been communicating with a patient through the ASCLS Consumer Web Forum who experienced a DVT and PE in 2014 and has been on Xarelto since then. Her physician routinely orders a D-dimer to assess the risk of a recurrence after discontinuing Xarelto. The patient stops Xarelto for 24 hours […]

Anticoagulant Therapy

ADAMTS13 Deficient Plasma

From Bhavna Gaikwad, Sekisui, Inc. Hi, I am in search for TTP disease state plasma, typically ADAMTS-13 deficient plasma (n=20) with the presence of antibodies, for our validation study. I would like to know the commercial suppliers for these clinical samples. Thank you. Hello, Bhavna Galkwad, and thank you for your inquiry. I know of […]

Load more

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.

Cheat Sheets from George

Quick Question