Basic Method Validation. Third Edition
320 pages, softcover, 2008.
James O. Westgard, Ph.D.
with contributions from:
- Elsa F. Quam, BS MT(ASCP)
- Patricia L. Barry, BS MT(ASCP)
- Sharon S. Ehrmeyer, Ph.D.
- R. Neill Carey, Ph.D.
- 23 Chapters
- Appendix on CLIA requirements
- Sample problem sets
- Self-assessment questions and answers
- New sections on ISO 15189 and ISO terminology Discussion of the new CLSI EP15 guideline
- Access to an exclusive ONLINE data analysis tool kit
Revised, Expanded, Essential!
For more than 30 years, Dr. James O. Westgard has been at the forefront of method validation and quality. After pioneering the method evaluation approach, he has consistently championed the proper techniques to validate and verify the performance of laboratory methods. With this third edition of Basic Method Validation, Dr. Westgard provides a crucial update on the tools and techniques of laboratory method assessments.
This third edition includes the following updates and additions - not available on the public website:
- Revised chapter on regulations that reflects the Final CLIA Rule as well as the latest CAP and Joint Commission requirements.
- Revised chapter on reportable range that includes calibration verification.
- Revised chapter on detection limit that describes the concepts of Limit of Blank, Limit of Detection, and Limit of Quantitation.
- Revised Method Decision Chart that includes the Six Sigma goal for
world class quality.
- New chapter on the estimation of trueness and precision based on the CLSI EP 15-A2 guideline, including directions for performing the required calculations.
- New chapter on evolving global standards (ISO) and the ISO 15189 standard, as well as the concepts of trueness and measurement uncertainty.
- New chapter that discusses how to translate method validation data into Sigma-metrics.
- Exclusive access to an online method validation toolkit that performs these validation calculations.
With the best of the previous editions and new material from the third edition, Basic Method Validation teaches you how to:
- Perform your method validation experiments quickly, efficiently, correctly!
- Choose the order of the experiments to save time!
- Collect the appropriate data for each experiment - without wasting specimens!
- Calculate the right statistics!
- Interpret the method validation results rationally!
- Judge the acceptability of the method, not the statistics!
- Establish a practical procedure for validating a method!
Basic Method Validation addresses healthcare professionals who perform laboratory tests in central laboratories, clinic or outpatient laboratories, and point-of-care settings. This concise, easy-to-read, 320-page manual contains a comprehensive introduction to method validation in the laboratory, from the conceptual idea of method validation to the bench-level specifics of planning an experiment:
- The inner, hidden, deeper, secret meaning behind method validation is revealed (i.e. why do we do what we do!).
- The requirements of CLIA, CAP, Joint Commission and other agencies are explained so you know what experiments your laboratory has to perform.
- All the experiments are explained in detail, from the number of specimens needed, how long the experiment should take, what problems to look out for, as well as (most importantly) what the numbers mean when you’re finally done.
- Practical experimental plans and worksheets are provided so readers can immediately evaluate and improve their current method validation practices.
Online training courses available!
- A short streaming video, "Secrets of Method Validation" gives an animated, narrated presentation of the core concepts of Method Validation.
- The comprehensive online course in Method Validation gives thorough coverage of all the studies discussed in the book.
- Site licenses available
Foreword to the Third Edition
Basic Method Validation is part of a trilogy of “back to basics” books that focus on analytical quality management. The other two books are Basic QC Practices and Basic Planning for Quality. When I teach these materials, I start with method validation because it introduces the basic concepts of analytical performance and the experimental and statistical techniques needed to describe performance in quantitative terms. These concepts carry through into the practice of QC and the selection of optimal QC procedures via quality design and planning.
The original source of this approach to method validation goes back thirty years to a series of papers that were published in the American Journal of Medical Technology and later as a monograph titled Method Evaluation. My co-authors were Diane J de Vos, Marian R. Hunt, Else F. Quam, R. Neill Carey, and Carl C. Garber, all of whom worked at the University of Wisconsin. We introduced this approach at workshops that were taught at the national ASMT and AACC meetings. Today Neill and Carl, together with David Koch, continue to teach this approach at the
AACC national meeting. They now hold the record for the longest running workshop in AACC history.
This third edition provides important updates based on new regulatory requirements and emerging standards of practice, particularly the latest guidelines from CLSI (Clinical and Laboratory Standards Institute):
- Updated CLIA regulations and accreditation requirements;
- Revised chapter on reportable range that includes calibration verification;
- Revised chapter on detection limits that includes concepts of Limit of Blank, Limit of Detection, and Limit of Quantitation, as recommended in the CLSI EP17 guideline;
- Updated “Method Decision Chart” that includes criteria for 2, 3, 4, 5, and 6-Sigma performance;
- New chapter on estimation of trueness and precision based on the CLSI EP15-A2 guideline, including directions for performing the required calculations using electronic spreadsheets;
- New chapter on evolving global standards (ISO, International Organization for Standardization), ISO 15189, and the concepts of trueness and measurement uncertainty.
- New chapter on Six Sigma metrics, including instructions on how to convert method validation data into Sigma metrics.
For more than thirty years, I have worked on quality control and method validation. While statistics, equations and calculations may not change, the context and the environment are constantly evolving. I hope this third edition helps you understand these method validation numbers in the proper context of your laboratory.
James O. Westgard
Basic Method Validation, Third Edition
|1. Is quality still an issue for laboratory tests?||1|
|Myths of quality||3|
|2. How do you manage quality?||13|
|The need for standard processes and standards of quality||15|
|3. What is the purpose of a method validation study?||27|
|MV - The inner, hidden, deeper, secret meaning||28|
|4. What are the regulatory requirements for method validation?||37|
|MV - The regulations, by Sharon S. Ehrmeyer, PhD||38|
|5. How is a method selected?||51|
|MV - Selecting a method to validate||52|
|6. What experiments are necessary to validate method performance?||61|
|MV - The experimental plan||62|
|7. How are the experimental data analyzed?||71|
|MV - The data analysis tool kit||72|
|8. How are the statistics calculated?||83|
|MV - The statistical calculations||84|
|9. How is the reportable range of a method determined?||101|
|MV - The linearity or reportable range experiment||102|
|Problem set - Cholesterol method validation data||102|
|10. How is the imprecision of a method determined?||113|
|MV - The replication experiment||114|
|Problem set - Cholesterol method validation data||122|
|11. How is the inaccuracy (bias) of a method determined?||123|
|MV - The comparison of methods experiment||124|
|Problem set - Cholesterol method validation data||135|
|12. How do you use statistics to estimate analytical errors?||137|
|Statistical sense, sensitivity, and significance||138|
|13. How do you test for specific sources of inaccuracy?||153|
|MV - The interference and recovery experiments||154|
|Problem set - Cholesterol method validation data||165|
|14. What is the lowest test value that is reliable?||167|
|MV - The detection limit experiment||168|
|Problem set - Cholesterol method validation data||175|
|15. How is a reference interval verified?||177|
|MV - Reference interval transference||178|
|16. How do you judge the performance of a method?||187|
|MV - The decision on method performance||188|
|17. What's a practical procedure for validating a method?||197|
|MV - The real world applications||198|
|MV - The worksheets||207|
|18. How do you use statistics in the real world?||211|
|Points of care in using statistics in method comparison studies||212|
|19. How can a manufacturer's claims be verified?||221|
|Verifying a claim for precision and trueness||222|
|20. How can claims be evaluated on the Sigma-scale?||241|
|Translating performance claims into Sigma-metrics||242|
|21. What impact will ISO have on analytical quality?||251|
|Quality Concepts: is it better to be uncertain or in error?||252|
|22. Self-Assessment Answers||273|
|Cholesterol Problem Set answers||300|
|Appendix 1: CLIA Analytical Quality Requirements||307|