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Antithrombin Affects the Anti-Xa Heparin Assay

Here is a question from my friend and colleague, Vicki Cardone at Children’s Hospital of Alabama, just down the street from UAB: I am having a hard time getting the concept behind finding a decreased anti-Xa level when you have decreased antithrombin (AT, antithrombin III, AT III). What part of the patient’s heparin is the […]

Mixing Studies

Hello George, I just completed the Quick Question concerning PTT mixing studies. Our PTT mixing study consists of two parts, a control of NPP and factor VIII deficient plasma tested immediately upon preparation and after 60 minutes incubation at 37 degrees. The patient is also mixed 50/50 with NPP and tested immediately upon preparation and […]

A New NovoSeven?

Here is an interesting note from M. Thabet: “Could you please forward the brand name and prescribing information for the new Russian version of recombinant factor VIIa (rFVIIa) similar to NovoSeven?” Thank you for your question. NovoSeven goes off-patent in the United States in 2011, and Novo Nordisk is developing both a fast-acting analogue and a prolonged […]

Specimens Collected in the Wrong Tube

Here is a note from participant “dsadowski” at Southampton Hospital: What are some guidelines for determining whether a specimen is citrated plasma vs. serum or another anti-coagulated plasma? My fibrinogen testing is PT-derived, so relying on a low fibrinogen value would not be helpful for determining serum vs. citrated plasma. Thank you for your question. […]

Qualitative Vs. Quantitative D-dimer

A message from “Dchrist” at Mercy Hospital in Chicago: What is the clinical rationale, if any, for offering both a qualitative and quantitative D-dimer assay in the main hospital lab? Hello, and thank you for your question. It may be that your director retains the qualitativeassay for a quick turn-around to help diagnose disseminated intravascular coagulation […]

Off-Label NovoSeven

Most transfusion services adopt a policy recommending Novo Nordisk’s recombinant activated factor VIIa (rFVIIa, NovoSeven®) in acute hemorrhage when conventional therapy; RBCs, frozen plasma, platelet concentrate, and cryoprecipitate fail to stop the bleeding. NovoSeven is FDA-cleared for prophylaxis or therapy in hemophilia A or B patients with inhibitors or people with congenital factor VII deficiency. When it is […]

Mixing Studies

I attended the Twelfth Annual Symposium on Bleeding and Thrombosis May 6 and 7 in Indianapolis. The meeting was sponsored by Midwest Coag Hemostasis and Thrombosis Laboratories and Esoterix, Inc. Laboratory Services and administered by Charles C. Miraglia, MD. I learned several interesting things at the meeting, but would like to feature a series of […]

Quick Question: HIT Testing

Our April Quick Question was “How do you test for heparin-induced thrombocytopenia (HIT)?” Here are the compiled answers: a. Platelet count only: 4 (8%) b. Platelet count and immunoassay: 22 (45%) c. Platelet count and heparin-induced platelet aggregation (HIPA): 10 (20%) d. Platelet count and serotonin release assay (SRA): 2 (4%) e. Platelet count, immunoassay, […]

Whole Blood QC for the PFA-100

A question from Jojie Acosta: After a lab inspection we are required to perform normal whole blood controls each day of testing for our PFA-100. Previously we only did the daily self-test on the PFA, though we ran QC on every shipment of cartridges. We currently have difficulty finding normal donors for the required daily […]

Quick Question Summary: Discard Tube

Our April, 2010 Quick Question was “Do you collect a discard tube prior to collecting a tube for coagulation testing?” Answers: a. Never: 14 (34%) b. Always: 14 (34%) c. Only for special coagulation testing: 13 (32%) For those who are collecting a discard tube in all cases, I have good new for you, you […]

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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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