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Mixing Studies Using a 4:1 Ratio

From Lester Jones at Triad: I am trying to find out what is the most effective mixing study ratio for lupus anticoagulants. Currently we are using a 1:1 mix for the DRVVT test. I think that a 1:4 would be better. What do you recommend? Hi, Mr. Jones, Reference labs may apply a 4:1 mix […]

Anti-cardiolipin Antibody Assay Validation

I’m posting this message from Patty Erickson at Vanderbilt for assistance from any of our RAQA gurus participating in the blog: Okay, I’m just not a chemist. I admit it. On my last CAP inspection I was cited for not performing AMR validations on my ELISA assays for anti-cardiolipin and beta-2 glycoprotein antibodies because I […]

Measuring Factor Inhibitors: Bethesda Titer

Here is a delightful message from my colleague Betty Ciesla at Morgan State University in Baltimore. Hi George, I am trying to explain the Bethesda titer, which I find difficult. My students do too. I understand you make a 1:1 mix of patient plasma and control plasma, incubate, test using the PTT then you make […]

Another Challenging PTT Question

Here is an interesting message from Twyla Bader at Peace Health: 1. What is a reasonable lower limit for reporting an APTT? We have Diagnostica Stago Compacts, our normal range is 23.0 – 35.0 seconds and our reportable range currently is 4.0 – 200.0 seconds. I don’t believe I have ever encountered a sample with […]

A PTT Discrepancy

I received this interesting question on Friday, October 3 from Priscilla Koernert: Hi George, I ran across your site while researching a method discrepancy regarding PTT results. We are currently using Stago Compacts obtained a result of 100.9 on a non-heparinized patient. The physician subsequently ordered further coag testing which we send over to the […]

Critical Low Molecular Weight Heparin Values

Here’s a summary of our September 22 Quick Question: What is your upper critical value for low molecular weight heparin therapy using the chromogenic anti-Xa heparin assay? Answers… What is your upper critical value for low molecular weight heparin therapy using the chromogenic anti-Xa heparin assay? None: 6 (46%) 1.0 U/mL: 2 (15%) 1.5 U/mL: […]

Comparison of Stago, Dade, BCI, and Other Equipment

Hi George, I like your site. Thanks for all of your effort! We are going to purchase a new coagulation analyzer soon and leaning towards the Diagnostica Stago instrument (STAR Evolution). Wanted to know what you and your colleagues thought about this instrument especially in comparison to the Dade and the Beckman (IL) instruments. Any […]

National Alliance for Thrombosis and Thrombophilia

I received this delightful message from Elizabeth Varga yesterday, and although her purpose was primarily to update our links to NATT from www.nattinfo.org towww.stoptheclot.org, I wanted to use this opportunity to draw attention to NATT and their excellent educational work. I’m happy to see Elizabeth is still involved and that NATT is going strong. Geo. Dear George: […]

The UDHT Assay and Cardiovascular Risk

Some new information on the use of the urine metabolite 11-dehydro thromboxane B2 (UDHT) is emerging from the CHARISMA trial involving 3200 subjects. Dr. John Eikelboom, McMaster University discussed UDHT as a predictor of cardiovascular risk at the European Society of Cardiology meeting September 1, 2008, and provided indications for reducing risk. The abstract is […]

Quest: Case-oriented Symposium

The Quest Diagnostics Nichols Institute “Case-Oriented Symposium on Bleeding and Thrombosis” is presented next week, September 24-25 at the Hyatt Regency in Reston, VA. The program has a number of excellent presenters and topics. I hope you can make it. Geo

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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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