5-Westgard Quality Control 4 Slides
5-Westgard Quality Control 4 Slides
5-Westgard Quality Control 4 Slides
Identify different approaches to Quality Control Describe the Westgard Rules and their use Evaluate the strengths and weaknesses of different QC strategies List the different options CLIA gives you for QC Assess the suitability of EQC and Risk Management for your laboratory QC
Outline
5 Possible Quality Control Strategies for non-waived test systems
1. 2. 3. 4. 5. Real World Standard Deviations from Good QC Westgard Rules: a multirule approach Ideal QC Design: Optimizing QC for tests CLIA Compliance QC Future of QC: Risk Management
Strategy #2: Westgard Rules What are they and why us?
Maximize error detection from few measurements Attempt to balance work with practicality Classic laboratory workaround Concept described 1977 Example posted 1981
official name: multirule Westgard Rules
Systematic error
Rules that count consecutive measurements beyond a certain limit 22s, 41s, 10x
Download from westgard.com
8x
8
Important to carefully define rules to be used and conditions for use across runs, across materials, etc.
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4
Simulation studies with patient data (Klee and Karon, 2010) Clinical Decision Intervals:
-6s -5s -4s -3s -2s -1s 0s 1s 2s 3s 4s 5s 6s Evidence-Based Medicine & Clinical Guidelines How do your Doctors use the Test? (BEST)
Strategy #4: QC compliance options from CLIA Whats possible under CLIA?
1. Do the right Statistical QC
Design the right rules and # of controls
2. Default QC
Just run 2 controls per day
3. Equivalent QC (EQC)
Maybe only 2 controls per week or month
4. Maybe Alternative QC
analytical process.
(b) must establish the number, type, and frequency of testing control materials
(c 1) The control procedures must detect immediate errors that occur due to test system failure, adverse environmental conditions, and operator performance;
(c 2) Monitor over time the accuracy and precision of test performance
Option 3. Device monitors none of analytical process. Evaluation: 2 levels/day for 60 days then Run QC once/week ( Is this based on Science? No. ) CMS admits in 2005: We blew it.
CMS sponsors development of Alternative QC (AQC) through CLSI: EP18, EP22, EP23 CMS Roles Out New CLIA Policy Changes CLN 2008
Legalizes Equivalent Quality Control (EQC)
Assemble Team
multidisciplinary
Risk Evaluation
Acceptability Matrix Criticality Prioritization
Occasional
Remote Improbable Acceptable Risk ?????
Assemble Info
Process map
Risk Control
Identify residual risks Develop control plan Implement controls
Risk Reduction
Analyze root cause Prevent Error Mitigate Error
Note the ????? Identifies cells where ISO 14971 classifies risk as unacceptable, but EP23 classifies risk as acceptable. Note also that Detectability has been eliminated in this matrix. Using Sigma-metrics for more quantitative matrices is allowed.
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How much effort does it take to conduct Risk Management for one process?
2009 review of 13 HFMEA projects in Dutch healthcare settings: (Lab HFMEA) Avg # team members = 7.2 (8) Avg # meetings = 6.3 (6) Avg # person-hours = 69.1 (72) Avg # failure modes = 51.8 (27) Avg # remedial actions = 16.2 (11)
Habraken, M. M. P., Van der Schaaf, T. W., Leistikow, I. P. and Reijnders-Thijssen, P. M. J.(2009)'Prospective risk analysis of health care processes: A systematic evaluation of the use of HFMEA in Dutch health care', Ergonomics,52:7,809 819
Self-Assessment Questions
Which of the following is a CLIA-acceptable QC strategy?
Anorexic QC Gambler QC Blind Man QC EQC options 1-3
3.
2.
Which CLSI Risk Management standard was proposed but then disbanded?
a) b) c) EP18 EP22 EP23
4.