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Adjusting for Hematocrit

CLSI Standard H-21A4 requires citrate volume adjustment when the hematocrit exceeds 55%. Yesterday, Terry Kotrla, MS MT (ASCP) BB, chair of the MLT program at Austin Community College posted a thought-provoking reference on Medlab-L, a 2005 MLO article by Roy Midyett elucidating and challenging this practice. I am curious about how we go about managing […]

Two Convenient Specimen References

Here are two informative specimen management links… …I learned about through a message from Mike Collins, BMS3, Clinical Biochemistry and Haematology, Norfolk and Norwich Hospital, Colney Lane Norwich NR4 7UY posted on the Medlab_L bulletin board: The World Health Organization pamphlet: Use of Anticoagulants in Diagnostic Laboratory Investigations and Stability of Blood, Plasma and Serum […]

Type 2 Antithrombin Deficiency: Dr. Moll

As you can see, I’ve been stumped by Dr. Moll’s question. I’ve reviewed assay menus for my favorite hemostasis laboratories… …in the US and Canada, including Esoterix, Machaon, Nichols, MidwestCoag, ARUP, and Hemostasis Reference Laboratory. All offer an antithrombin (ATIII) activity and immunoassay, but none has a phenotypic assay for type IIb deficiency nor genotypic […]

Anticoagulation Forum and CYP2C9

Kim Kinney’s response about monitoring for CYP2C9 polymorphisms reminded me of last summer’s Anticoagulation Forum exchange between… …Dr. David Garcia, Anticoagulation Forum president and Lawrence J. Lesko, PhD, FCP regarding the FDA’s plan to require information in the Warfarin package insert about genomic testing. There are some differences of opinion about the efficacy of genomic […]

Type 2 Antithrombin Deficiency: Dr. Stephan Moll, UNC

George, I noted your new website-blog. Interesting activity. I will challenge you with a question: 33 year old woman with type 2 antithrombin deficiency (AT activity – chromogenic Xa inactivation assay in the presence of heparin – HemosIL Liquid Antithrombin) is 58 % (normal 88 and above) twice, from from 2 separate blood draws. AT […]

The Butterfly

I sent out some announcements for our blog last week and received some nice responses from colleagues and former students. I heard from Francy Van Dyke who graduated from one of my earliest classes in Peoria, back when the Earth was forming (sorry, Francy). One of the facilities she works with prohibits… …home health care […]

Genomic Screening for Warfarin Therapy

Last Tuesday I attended a School of Public Health doctoral dissertation defense at the University of Alabama at Birmingham on the subject of testing CYP2C9 and VKORC1 polymorphisms… …prior to warfarin therapy. There is a discussion of this by Sconce, Khan, Wynne et al, Blood 2005; 106:2329-33. The UAB dissertation was a prospective study comparing […]

Should We Add AT To The Mix?

From Bob Gosselin at UC Davis: What is truth? Do we supplement with antithrombin (AT)… …or not in measuring UFH by anti-Xa activity. As you know, there are significant differences in anti-Xa levels when one supplements with AT. This would obviously impact the heparin therapeutic range for aPTTs. Toss in the Dade method which supplements […]

Is There Another Factor XIII Assay? (Pam Owens)

A note from Pam Owens at TriCore Reference Laboratories: We have seen a reference to a Factor 13 assay using thrombin and acetic acid as opposed to 5M urea. Does anyone have experience with this method? Where can we get a copy of the protocol?

Should we Discard Discard Tubes?

Please review our previous thread on specimen collection and the comment on discard tubes. Except for “butterfly” infusion sets, when we use a discard tube to compensate for air in the tubing, discard tubes are contraindicate. See McGlasson DL, More L, Best HA, et al. Drawing specimens for coagulation testing: is a second tube necessary? […]

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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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