ClotCare Webinar

The Coalition to Prevent Deep Vein Thrombosis is hosting a free webinar on DVT issues today, Wednesday, January 27, 2010 from noon to 1:00 PM EST.  The webinar is intended for patients and others wishing to learn about the prevention, diagnosis, and treatment of deep vein thrombosis (DVT).  DVT Coalition member and ClotCare Editorial Board member Ruth Morrison, RN, BSN, CVN will be the presenter for the free webinar.

Cumulative Summation Lot-to-Lots For PTTs

This message from Randy Trussell at Tenet Health arrived January 4. Randy, sorry for the delay, and I hope this is still helpful.

(There is a direct response from Dr. Olson appended to the end of George’s response.)

Our lab established the unfractionated heparin (UFH) therapeutic range last year using the Brill-Edwards approach. This year we are evaluating our partial thromboplastin time (PTT) reagent lot change using the cumulative summation (CUSUM) of differences method described by Dr. John Olson in the October, 2004 CAP Today. Dr. Olson suggests the computing the CUSUM of the mean values to correlate old and new lots.

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Automated Ristocetin Cofactor

Here is a question I received early in January from Elpidio Pena. I apologize to Elpidio for letting this one slip through the cracks.

George: our lab performs the ristocetin cofactor (VWF activity) assay using the traditional platelet aggregation method. We are planning to change instruments and one of the instruments we are considering performs the assay by ELISA (coated beads). Any advantages/disadvantages on the ELISA method? Any particular issue to consider with this method?

Thanks.
Elpidio Pena

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Therapeutic INR for Mechanical Heart Valves

Here are the results for last week’s Quick Question:
What is your target INR therapeutic range for patients who have a mechanical heart valve?
a. INR: 1.0-2.0: 2 (3.8%)
b. INR: 2.0-3.0: 5 (9.6%)
c. INR: 2.5-3.5: 40 (77.0%)
d. INR: 3.0-4.0: 5 (9.6%)
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Screening for Heparin During LA Testing

Hi, George!

I’m curious to know how other labs handle routine detection of heparin in samples for lupus anticoagulant testing. We currently run a PT and PTT on all samples right off the bat and then Hepzyme any that have high PTTs before proceeding with testing.
As a quality management project, we are comparing other methods (like running thrombin time before Hepzyming) to see what’s most efficient and cost effective.  We do a fairly large volume of lupus profiles here and sometimes end up Hepzyming 10 or 15 samples a run, many of which don’t correct of course.  Any feedback is appreciated!

Thanks,

Krista Hostetler, MT (ASCP)
Special Hemostasis Laboratory
Emory Medical Labs
Emory Healthcare, Atlanta, GA

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Wilate von Willebrand Factor Cleared

Gerald Sapp, University of Alabama at Birmingham transfusion service manager told Margaret Fritsma, MA SBB (ASCP)–who then told me–that Octapharma USA announced their human plasma-derived biological, Wilate® von Willebrand factor/coagulation factor VIII complex was cleared by the FDA 12/4/09. Click these links for Octapharma’s Wilate brochure and package insert.

Gerald wanted to know if anyone has experience with Wilate, and whether it is a valid substitute for Humate-P. I would also like to know if it can be monitored using the same methods, ristocetin cofactor (VWF:RCo) and factor VIII, as are used to monitor Humate-P. If you are using Wilate, please provide your information using the comments link. Thanks, Geo.

New Web Site: Thrombosis Clinic

Stephen Duff of Precision BioLogic introduced me to an excellent new web site, ThrombosisClinic.com. The site offers a number of CME programs in hemostasis. Geo.

Critical INR Values

I received this question from Emily Oakley at Windy Hill. Emily also posted this question to Pat LeTendre’s Medlab List last week: “How high should INRs be reported?” Emily, fortunately, this was the subject of a Quick Question in August of 2008. Please select the link for a summary of our findings at that time. I’d also like to point you to Olson JD, Brandt JT, Chandler WL, et al. Laboratory reporting of the international normalized ratio: progress and problems. Arch Pathol Lab Med 2007;131: 1641-7. The article sets the maximum reportable INR at 9.0 Thank you for your valuable question. Geo.