All Posts

D-dimer Versus FDP

From FD Patel, MD: I had a patient here who was tested for both FDP and D-dimer. Her D-dimer was mildly elevated at 0.79 but her fibrin degradation products (FDP) assay result was undetectable. Since the D-dimer is a type of fibrin split product, how can you explain this discrepancy? I’m thinking it has something to […]

MTHFR Double Heterozygote?

A question from a colleague: My relative is 35 and is currently about 20 weeks pregnant. She has 2 healthy children, but has also had two miscarriages in the past three years. She is a double heterozygote for MTHFR C677T and A1298C. If I am interpreting the literature correctly, the double heterozygosity should not increase […]

Incubated PTT Mix: What Constitutes Correction?

From Sylvia Bunting, Children’s Healthcare of Atlanta: We do an immediate and incubated mixing study. For deciding on whether there is a time-dependent inhibitor, what criteria do you use to decide that the PTT was prolonged after incubation? Any prolongation beyond the immediate mix PTT? Thanks. Hi, Sylvia, and thank you for your question. If the PTT […]

Lupus Anticoagulant

Intermountain States Seminar September 26–29

I hope you can attend the 49th Annual Intermountain States Seminar at the Snow King resort and Virginian Lodge this week in Jackson, Wyoming, September 26–29. I (George) will speak on “Monitoring the New Anticoagulants, Whatever Happened to the PT and PTT?” 1:45–3:15 and “Managing Hemophilia Therapy, from Rasputin to Recombinants,” 3:30–5:00 on Thursday, September 27 at the […]

Elagic Acid-based PTT Reagent

From Kelly Rose at Novartis: Hi George, I work in a research lab and we are interested in comparing different partial thromboplastin time (PTT) reagents on our Stago Sta-R. Currently we use the silica-based (STA PTT-Automate) and kaolin-based STA C. K. Prest. We would like to try ellagic acid. Have you had any experience with this reagent? and […]

Screening Assays

Reduce Blue-top Tube Volume?

From Maria E. Martinez. Is anyone re-adjusting anticoagulant levels in blue tops? We atOrlando Health have a large NICU and collecting a 2 mL blue top sometimes can be a huge demand. I have heard of re-adjusting the 200 uL anticoagulant in the 2 mL blue top to 100 uL and instructing the nurse to draw up […]

Specimen Management

Tissue Thromboplastin Inhibition Test

Here is a question that appeared on the Clinical Laboratory Science (CLS) Educators’ list: “We are trying to figure out the principle, procedure for the tissue thromboplastin inhibition (TTI) test. We are aware that it seemingly is no longer performed, but feel there is a good chance that the ASCP could potentially ask questions about […]

Lupus Anticoagulant

Factor Assays: How to Define Parallel Results

From Maria Franco, Orlando Health: Hi, George, when running factor assays (1:10, 1:20, etc), is the agreement between results to r/o inhibitory activity all calculated from the original result (1:10)? Not sure what the most common or recommended practice is. I have heard to find the mean of all results and then try to calculate the deviation. […]

PTT Reagent LA Sensitivity in Mixing Studies

Hello George, My name is Marcelo Gonçalves, clinical pathologist from Hematology Department of Hermes Pardini Laboratory, Brazil. I would like to ask what kind of activated partial thromboplastin time (APTT, PTT) reagents should be used in APTT mixing studies (high or low responsiveness to LA)? Thank you for your attention. Dr. Marcelo Luide Pereira Gonçalves Thank […]

Lupus Anticoagulant

Validating High POC INR Results

Our April 24, 2012 post (and Quick Question), POC: When to Validate a High INR has attracted a provocative comment from Alan Neal of New Zealand. I’ve added this link so the comment does not get buried and to attract additional discussion from our participants.

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