Validation

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 […]

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

What is NASCOLA?

I (Geo) enjoyed dining with our NASCOLA colleagues on Wednesday, 7 May 2025, while attending the 2025 ISLH annual meeting in Halifax, NS. NASCOLA is a nonprofit organization that provides proficiency testing services for North American laboratories that perform diagnostic testing for bleeding or thrombotic disorders, thereby improving performance standards. NASCOLA reviews and assists with […]

Lab Developed Tests Rule

Thanks to PBI’s Dean Willett for his heads-up about the March 31, 2025 ruling, “FDA‘s LDT Rule Struck Down in Texas Court.” The US FDA‘s 2024 “Final Rule” outlined plans to subject lab-developed tests to the same requirements as medical devices. The Texas ruling illustrates the US struggle to achieve a realistic approach to validation […]

How to Improve Lab Testing

From Heather DeVries: In the scope of the whole world, how do labs search for new ways to improve their laboratory testing? Would it just be typing in the search bar, or are there ways to find the latest information randomly while looking for other things? George replies, Heather, my surface-level response is to suggest […]

Specimen Management

Differential Discussions: VWD Type 1 and RCo.

Thanks to Malissa Norfolk and David Calder for our Differential Discussions conversation describing the time-honored Ristocetin Cofactor (VWF:RCo) test for von Willebrand factor activity, a member of the von Willebrand disease diagnostic assay, released January 1, 2025 on YouTube. Please click the link and join the discussion.

Bleeding Disorders

Hot Topics in Hemostasis: Nomenclature Standardization

Frequent contributor David L. McGlasson is featured in the Differential Discussions series hosted by Assistant Professor David Cabral, MBA, MLS(ASCP)cm, SH(ASCP)cm of the University of Massachusetts Dartmouth, and Assistant Professor Malissa Norfolk, MBA, MLS(ASCP)cm, SH(ASCP)cm, of the University of Maine-Augusta faculty. Click here to meet Malissa and David, and to hear Mr. McGlasson’s discussion of […]

Coagulation Factors

VKA Monitoring in Hepatic Insufficiency

Here is a challenging case from Hrvoje Melinšćak sent 5-30-24: Dear George, In hepatic insufficiency there is often a prolonged basal protime, how to ensure therapeutic values of warfarin when the INR is already elevated? This is of particular concern in those with mechanical cardiac valves. Serum warfarin levels (spectrophotometry) are cumbersome and take days to […]

How to Measure Plasma Efanesoctocog Alfa [Altuviiio]

For those like me (Geo) who are just learning of it, efanesoctocog alfa (Altuviiio™), US FDA-approved in February of 2023 is Sanofi/Sodi’s extended half-life synthetic FVIII concentrate. Here is an edited description of Altuviiio’s structure and PK from the package insert. Altuviiio (efanesoctocog alfa, ehtl, recombinant AHF, Fc–VWF-XTEN fusion protein) replaces missing FVIII needed for […]

Bleeding Disorders

Hemostasis Quality Control Modules

Fritsma Factor is pleased to introduce our most recent audio PowerPoint modules, Hemostasis Quality Control Part 1 and Hemostasis Quality Control Part 2. These modules were produced by friend, colleague, and co-author Mayukh Sarkar, Ph.D MLS [ASCP] for the Rutgers University 2023 graduate course, Advanced Hemostasis CLS5124. Dr. Sarkar has a wealth of QC experience […]

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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

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