Join George as he kicks off the American Association of Clinical Chemists (AACC) Quick Takes webinar series with “Quick Takes on Quality Assurance in Hemostasis.” George will present three 30-minute presentations on August 7, 14, and 21, 1–1:30 EDT. He will discuss:
- Employing local calibration for prothrombin time/international normalized ratio (PT/INR) monitoring of Coumadin therapy.
- Specimen management for coagulation and platelet aggregometry
- Determining PTT sensitivity to factor VIII and IX deficiency
- Developing an ex vivo “Brill-Edwards” curve to establish the partial thromboplastin time (PTT) heparin therapeutic range
- Calculating clinical sensitivity and specificity and computing receiver-operator curves (ROC analysis)
From Odetta Hanna, Coagulation Applications Specialist at Sekisui Diagnostics: I was wondering if you could help me locate references or resources to support a statement that I made for Method Comparison: Coagulation: Interpretation of results. I am writing a method comparison procedure and I referenced CLSI EP09-A3. However, I cannot locate any specific supporting documentation for the statements listed below. The second bullet highlighted in red, is the one I need the most help with.
Thank you for any help that you can provide. Read more »
From Kelly Townsend, Tri-core Reference Laboratories, Albuquerque. Looking for opinions on what constitutes a “Laboratory Developed Test” in Coag. Obviously if the reagent kit is not FDA-cleared, it will be an LDT, but what about factor assays, etc where there is no real kit. What if you are using a kit with a different calibrator or control than the manufacturer sells/endorses? Having trouble coming up with a concise definition for LDT. Thanks, Kelly.
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From Julia Nailling: What delta checks do laboratories commonly use for autoverification of prothrombin time with international normalized ratio (PT/INR), partial thromboplastin time (PTT), fibrinogen, and D-dimer?
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Maria Grana writes, Hello George, what would constitute a “significant change” when performing the yearly reference range study for coagulation? Thanks.
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Here’s an additional note confirming Denise Solieau’s February 12 discussion of PT validation and analytical measurable ranges (AMRs). Page 83 of the July 31, 2012 CAP survey references the value of AMRs in coagulation testing and includes this statement, “The new checklist requirements (meaning AMR) apply to hemostasis test methods that are calibrated and directly measure the concentration or activity of an analyte by employing enzyme immunoassay (EIA) immunoturbidity, and chromogenic methods. Clot-based methods, euglobulin lysis time, qualitative clot stability, and all platelet function assays, including ristocetin cofactor activity are exempt.”
From Purvi Jariwala, Texas Children’s Hospital:
Hi George, There is a new CAP checklist requirement published 7/31/2012. Heme.38009 AMR validation: “Validation of the analytical measurement range (AMR) is performed with matrix-appropriate materials, which include the low, mid and high range of the AMR.” I wanted to post this on your site to see how other laboratories will be addressing this requirement.
Hello, Dr. Jariwala, and thank you for your post. Let’s await comments from our correspondents.
Thanks to those who attended our American Society of Clinical Pathology Laboratory Statistics and Quality Control workshop on Friday, October 5 in Minneapolis, MN. I hope we met your needs. As promised, I’ve attached 6-per-page PDFs of my first and last lectures, Pre-analytical and Post-analytical Variables. These are the lectures that contained updated slides not provided in your original handout. Also, for those who would like to have access to our 32 audio PowerPoints, please select this link. Modules 3-6, Method Validation and Clinical Efficacy are similar to the materials we discussed during the workshop. All the audio PowerPoints are approximately 30″ long and lead to CEU credit through CACMLE. Again, thanks for participating. Geo