Instrumentation

Clot Waveform Analysis

Click here for this open-access article on waveform analysis and for access to Seminars in Thrombosis and Hemostasis Issue 4, 2026: Tan JY, Raden M, De Guzman T, Wong WH. Decoding clot waveform analysis: toward better understanding and harmonization. Semin Thromb Hemost 2026; 52(04): 460-475 DOI: 10.1055/a-2778-9810. Abstract Clot waveform analysis (CWA) extends routine coagulation […]

Global Hemostasis Assays

FXI and XII Non-parallelism Puzzle

Sacha Uljon, MD, PhD, Medical Director, Core Laboratory, Massachusetts General Hospital, sends us an FXI and FXII puzzle: This is a question for Werfen ACL Top users: We have noticed non-parallelism for FXI and FXII, increasing factor levels with increasing dilutions, even in patients without LAC. We’ve done a lot of troubleshooting; this seems to […]

Hemostasis Assay Statistical Variability

Here is an open-access commentary that addresses concerns about hemostasis assay statistical variability as it relates to clinical significance. Click: Mullier F, Gouin-Thibault I, Meijer P, et al. Time to integrate measurement uncertainty in method comparison and interpretation of hemostasis laboratory assays. Res Practice Thromb Hemost 2025: 9, https://doi.org/10.1016/j.rpth.2025.102993. For a two-part discussion about hemostasis quality assurance […]

January 2025 Quick Question: PFA 100/200

Our January 2025 Quick Question asked: “To test for platelet function, how do you report PFA-100/200 collagen-epi (CEPI) and collagen-ADP (CADP) results?” Here are the responses from 35 participants: CEPI only, Neg/Pos: 1 (3%) CEPI only, CT seconds: 2 (6%) CEPI & CADP, Neg/Pos: 3 (9%) CEPI & CADP, CT: 23 (66%) We use the […]

Quick Question Archive

DIC and Hemolysis

Anne D’ Agostino asks, “Should we reject hemolyzed samples from someone in DIC?” The simple answer is “do not reject,” because the hemolysis is likely intravascular, reflecting DIC‘s microangiopathic hemolytic anemia [MAHA]. But to elaborate, there’s no foolproof way to differentiate intravascular [in vivo] hemolysis from spurious [in vitro] hemolysis, the consequence of specimen collection […]

Bleeding Disorders

Poster: a Handheld Fibrinogen Assay Device

The qLab FIB is a recently introduced handheld point-of-care device that returns a fibrinogen result within ten minutes using a single drop of citrated whole blood.

OR Hemostasis Presentation

I [Geo] will present “Hemostasis in the Operating Room” at the American Society for Clinical Laboratory Sciences Joint Annual Meeting in Grand Rapids, Michigan, Wednesday, tomorrow, June 29, 1:45–2:45 EDT. The “JAM” will be a hybrid meeting, so presentations will be available on-site or online. My talk covers anticoagulation and coagulopathy management and features the […]

Global Hemostasis Assays

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

CoaguCheck Test Strip Recall

Thanks to Ali Sadeghi-Khomami PhD, Precision BioLogic, and Joan Polancic, MS MLS, Denver Health, for the heads-up on this announcemment: Roche Diagnostics, the manufacturer of CoaguChek meters and test strips, is recalling the CoaguChek XS PT Test Strips due to inaccurate INR test results, when compared to laboratory results. Roche re-calibrated the CoaguChek XS PT […]

Anticoagulant Therapy

Effect of HCT on POC INR

George received this question from the ASCLS Consumer Web Forum via Bonnie Jo Taylor, MHS, MT(ASCP)SH. I have hemochromatosis, too much iron in my blood. I’ve also had blood clots in my lungs. I peroidically undergo phlebotomy treatments to lower iron count. Will this alter the results of my INR finger prick test results? Here […]

Anticoagulant Therapy

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