Category: Validation

Delta Checks

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?

Read more »

Reference Range Change Limit

Maria Grana writes, Hello George, what would constitute a “significant change” when performing the yearly reference range study for coagulation? Thanks.

Read more »

More on PT Validation and AMR

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.”

AMR: Matrix-appropriate Materials

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.

ASCP Statistics and QC Workshop

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

Preanalytical Variables

Postanalytical Variables

Anyone Using Six Sigma?

Hi George, Thanks for all the great information on the website. I have a question regarding the use of Six Sigma in the coagulation laboratory. Do you know of, or are there any laboratories that are using Six Sigma to monitor the quality of testing in coagulation? We know these concepts may be used in the chemistry lab as explained by Dr. Westgard during the Mayo meeting, although I don’t know of any coagulation lab using the same concepts. Thanks for any feedback, Claudia E. Escobar, MT (ASCP) SH, Diagnostica Stago, Inc., Area Manager – Latin America.

Read more »

Normalized DRVVT Ratio?

George has had several conversations with frequent contributor and international expert Dave McGlasson (Wilford Hall USAF Medical Center, San Antonio) about normalizing the DRVVT ratio on the laboratory’s DRVVT mean of the reference interval in accordance with Zhang L, et al: A simplified algorithm for the laboratory detection of lupus anticoagulants. Am J Clin Pathol 2005;124:894–901. The author states, “The normalized ratio is recommended to correct for differences in instrument-reagent combinations and to improve discrimination between normal and low-positive LA samples. The formula for normalization is attached in this link: DRVVT Normalization Ratio.

Read more »

How to Validate an Aggregometer

From Rrosales:

I am interested in purchasing a platelet aggregometer for our hematology lab, but we don’t have an existing instrument to compare it with. Some suggested H58 NCCLS (CLSI, does not really help) but I am used to validating an instrument with an old instrument (comparison/parallel testing). Can you tell me how to start the validation without an instrument to compare it with and does CAP allows this method?

Read more »

WordPress Themes