Mixing Studies

Mixing Studies; Rosner Index

From Dr. Aliaa Mohamed Amer, Senior Consultant Hematopathologist, Hamad Medical Corporation, Qatar: What is the value of calculating the Rosner index on the incubated plasma 1:1 mix (patient and control)? Does the cut-off used for the direct mix apply to the incubated mix? My understanding is that the Rosner index is primarily useful for the detection of […]

Heparin and Mixing Studies

From colleague Brenda Goforth, Senior CLS Hematology, Coagulation, and Urinalysis | Clinical Laboratory, Antelope Valley Medical Center Hi George, When using Hepzyme on patients who are on heparin and a mixing study is ordered, what is the standard for when neutralization is complete? If the PTT is normal after one neutralization, then proceed to 37ºC incubation, but what […]

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 […]

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 […]

PTT Mixing Study Prolongs Instead of Shortening

This is a prior-year post that has resurfaced as we have switched over to our new provider and format.

New FVIII Inhibitor Assay

An exciting news release from Precision BioLogic Inc. Today, we are announcing the availability of our new CRYOcheck Factor VIII Inhibitor Kit in Canada, the European Union, Australia, and New Zealand following market authorization by Health Canada and respective in-country regulatory authorities in January. Click here for full information about the CRYOcheck Factor VIII Inhibitor […]

Bleeding Disorders

Follow-up to Incubated Mixing Studies

Referring to Ruth Spates’ June 18, 2018 question about mixing studies followed by Dr. Paul Riley’s comment asking why we incubate two hours, Dr. Connie Miller of the CDC answered today with reference to a 1974 publication that establishes hemophilia A inhibitor (anti-FVIII) kinetics. Click or tap here for the full 1974 article, Allain JP, […]

Platelet Neutralization Procedure

Geoffrey Wool, MD, PhD, Associate Director of Coagulation at the University of Chicago Medical Center Laboratory, provided an excellent Webinar, “Lupus Anticoagulant Testing: Managing Interferences and Optimizing Quality” on the Labroots provider site. Dr. Wool addresses among other issues the time-honored platelet neutralization procedure (PNP), in which concentrated phospholipid extracted from platelets is used to […]

Incubated Mixing Studies

From Ruth Spates: Hi George, our mixing study procedure requires the patient plasma and the pooled plasma to be incubated separately, and then mixed, and the PT or PTT performed. This is in addition to the 1:1 mix being incubated and retested, and the separately incubated patient plasma and NPP to be retested. I don’t […]

Prothrombin Time Mixing Studies

A colleague recently contacted George about prothrombin time mixing studies. Apparently, the College of American Pathologists provided a PT mixing study challenge in a recent survey. George discussed PT mixing studies with Fritsma Factor advisers Larry Brace, PhD and Dave McGlasson who helped list reasons for not doing them: Reasons for not performing a PT […]

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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.

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