All Posts

When Do We Titer Inhibitors?

Dana Carton asks, “We currently test for factor inhibitors using the clot-based Bethesda titer as well as a chromogenic bovine assay for Hemlibra patients no matter what the factor level. We recently learned that colleagues don’t look for that inhibitor unless the factor level is less than 5%. Is this a common practice, and would […]

Indirect Reference Interval Determination

Sarkar MK, Fritsma GA, Chapter 3, Quality Assurance in Hematology Testing; Keohane EM, Butina MM, Mirza KM, Walenga JM. Rodak’s Hematology: Clinical Principles and Applications Edition 7 states the following: “Indirect RIs may be derived from stored patient data. The QC specialist mines the laboratory database to compute the mean and confidence interval. Indirect RI […]

Video: Have We Cured Hemophilia?

Click here to view my (Geo) video, Have We Cured Hemophilia?, recorded with Professors Malissa Norfolk and David Cabral as part of their series, Differential Discussions. Part One reviews the history of hemophilia management from the time the first antihemophilic factor was produced to 2014 when turned to the extended half-life hemophilia concentrates.

Bleeding Disorders

Manual Tilt Tube PT

Here is an open-access editorial commenting on the tilt-tube PT requirement for establishing the reagent thromboplastin ISI. Favaloro EJ. Manual tilt tube method for prothrombin time: a commentary on contemporary relevance. Clin Chem Lab Med. 2025;63:1239–42. doi: 10.1515/cclm-2025-0157. PMID: 39985393.

Screening Assays

Inaccuracies of Venous Thromboembolism Risk Assessment

This April 2025 article indicates a ~29% under-reporting of VTE risk in a cohort of medically ill patients: Lau B, Bhave A, Yui JC, et al. Inaccuracies of venous thromboembolism risk assessment and prevention practices among medically ill patients. Blood Adv. 2025:bloodadvances.2024015306. doi: 10.1182/bloodadvances.2024015306. Epub ahead of print. PMID: 40408310.

Updated DIC Parameters from ISTH

The ISTH SSC Subcommittee on Disseminated Intravascular Coagulation has published its latest definition and scoring system for DIC. Click below for the open-access article. Iba T, Levy JH, Maier CL, et al. Updated definition and scoring of disseminated intravascular coagulation in 2025: communication from the ISTH SSC Subcommittee on Disseminated Intravascular Coagulation. J Thromb Haemost. […]

Bleeding Disorders

What is PITT?

Click below for an open-access article that classifies VITT and HIT as members of a platelet factor 4 (PF4) disorder, anti-PF4 mediated thrombocytopenia and thrombosis (PITT). Nicolson PLR, Montague SJ, Buka RJ, et al. Anti-PF4 mediated thrombocytopenia and thrombosis associated with acute cytomegalovirus infection displays both HIT-like and VITT-like characteristics. Br J Haematol. 2025. doi: […]

Arterial Thrombosis

Webinar Summarizes ISLH Meeting 7–9 May, 2025

Click here to see our Precision BioLogic Inc. webinar summarizing our activities at the 7–9 May ISLH meeting in Halifax, NS, featuring PBI scientific staff Jon Geske, Ian Burns, Stephanie Henneberry, Mushfigur Rahman, and Tara Quinton. I (Geo) added a presentation describing the NASCOLA meeting. NASCOLA typically schedules its annual meeting to coincide with major […]

COVID-Coag Information

Early in 2021 Fritsma Factor published a narrated 40-minute PowerPoint file named COVID-Coag. While it may seem dated, the presentation links the SARS-Cov19 virus to acute inflammation, platelet activation, DIC, SIC, TMA, TTP, and VITT (recently categorized as “PITT“), insights born of our intense studies of the pandemic. Further, this article appears in the April […]

Agent Orange

This entry was in response to a question from Dennis Brondi: “Hi–I was exposed to Agent Orange and have primary APS (also single parent factor V Leiden). Do you know of any studies establishing causation between AO and APS? My issues have included avascular necrosis of both femoral heads and multiple large DVTs from the […]

Bleeding Disorders

Load more

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