Validation

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 […]

More on CaCl2 Validation

We recommend you return to our February 4, 2024 entry that discusses CaCl2 validation. We’ve received additional comments including a comprehensive response from several expert CAP staff members.

April 2022 QQ: Measuring Heparin

Our April 2022 Quick Question reprises our May 16, 2012 post, “Who Uses the Hybrid Curve?” but adds a twist based on May JE, Siniard RD, Taylor LJ, Marques MB, Gangaraju R. From activated partial thromboplastin time to anti-factor Xa and back again; the evolution of monitoring unfractionated heparin. Am J Clin Pathol 2022;157:321–7 HTTPS://DOI.ORG/10.1093/AJCP/AQAB135. […]

Anticoagulant Therapy

More on Geomean: Instrument Specific or System-Wide?

A recent comment [click] from Dr. Emmanuel Favaloro on our November 9 discussion of a system-wide geomean was posted 12/15/21.

Geomean: Additional Information

From Hillary Thurman: Here is some additional information, in response to Bob Gosselin’s 11-6-21 response: The RIs currently in use are the manufacturer’s suggested ranges. Each site collected screened normal samples and EP Evaluator was utilized to ensure the patient population did not fall outside this range. Each site (there are seven) currently has one […]

Geomean: Instrument Specific or System-Wide?

Hillary Thurman is looking for some insight, She writes, “We have recently standardized hemostasis instruments across our system. The rest of the system has been using a combined geometric mean for their PT reagent (same lot, same instruments), but my site has never been involved in this. In addition, they do not change the geomean […]

Hemostasis in Selected Populations

In Keohane EM, Otto CN, Walenga JM: Rodak’s Hematology; Clinical Principles and Applications, Sixth Edition, 2020, Dr. Linda Goossen provides a timely and clinically significant chapter, “Hematology and Hemostasis in the Pediatric, Geriatric, and Pregnant Populations.’ Owing to next-generation sequencing, the In-Vitro Diagnostics world continues to partition reference intervals, therapeutic target ranges, and treatments to […]

Factor IX Assay Unexpected Results

Mike Meyer asks, “we run three dilutions for all of our factor testing. Occasionally, we see results in which upon higher dilutions, the factor value decreases after adjusting for the dilution. For instance, I had a case today in which the FIX values were 0.64, 0.55, and 0.43 U/mL for the 1:10, 1:20, and 1:40 […]

Bleeding Disorders

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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.

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