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Quality Control. David Korcal , BSMT, (ASCP). The monitoring of results obtained from the performance of a standard operating procedure Test results Results obtained from a process. What is Quality Control?. “Quality has to be caused, not controlled.” Philip Crosby, Reflections on Quality.
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Quality Control David Korcal,BSMT, (ASCP)
The monitoring of results obtained from the performance of a standard operating procedure Test results Results obtained from a process What is Quality Control?
“Quality has to be caused, not controlled.” Philip Crosby, Reflections on Quality
5.9 Ensuring the quality of test results The laboratory shall have procedures for monitoring the validity of test results. This monitoring shall be planned and reviewed and may include, but not be limited to, the following: internal quality control schemes using statistical techniques (e.g., control charts); where applicable, use of international reference reagents for preparation of national and/or working standards for internal quality control; when practical, replicate tests using the same or different methods; correlation of results for different characteristics of a specimen or sample; re-testing of retained specimens or samples; participation in interlaboratory comparison or proficiency testing programs NOTE: The validity of test results is influenced by both technical competence and assay performance characteristics. If the validity of test results is called into question, it is important to be able to distinguish between the two. A test may demonstrate appropriate process control but poor diagnostic performance or vice versa. AAVLD Essential Requirements
Procedure Required Planned QC Monitoring and Review Document all Control Results Record Controls in a method that is conducive to monitoring and review Document monitoring and review The laboratory shall have procedures for monitoring the validity of test results. This monitoring shall be planned and reviewed …
Where applicable: Use appropriate statistics Use recognized standard control material Replicate test Consider specimen evaluation Utilizing retained specimens Inter-laboratory comparison Proficiency testing Choose the appropriate Quality Control Methods
Internal Quality Control Schemes Using Statistical Techniques
Quantitative assays: Examples: Glucose, Serum Platelet Count Total T4 Cortisol Blood Lead Ethylene Glycol, Quantification Vitamin E Selenium PCR CT Values Quantitative RID testing ELISA OD Values Where applicable monitor using appropriate statistics
Quantitative Statistical Tools: Mean SD CV Z-Stat Six Sigma Quantitative Evaluation Tools: Multi-rules LJ Charts Where applicable monitor using appropriate statistics
Qualitative assays: Examples: IFA ELISA PCR Direct Coombs IHC FA Where applicable monitor using appropriate statistics
Qualitative Statistical Tools: Frequency % Failed Control Results % Acceptable Control Results Drift (Shift) Qualitative Evaluation Tool for: Reagent Stability Control Stability Environment Stability Technologist Competence Where applicable monitor using appropriate statistics
Where applicable, use of international reference reagents for preparation of national and/or working standards for internal quality control
Examples: NIST Material ATCC Organisms Commercial materials from recognized sources Use recognized standard control material
Calibrator Vs Control Calibrator: A recognized material that is used to adjust the output of a method. Control: Material used to monitor a method. The result of which is compared to an expected outcome. Note:The material used to calibrate a method should not be used as a control to monitor that method. Use recognized standard control material
Determining factors: Availability Cost Need Use recognized standard control material
When practical, replicate tests using the same or different methods
Examples: Running an ELISA in duplicate Confirm a positive HPLC test with LCMS Confirm IHC results with culture Replicate Tests
Advantages: Improves the assay precision Result confirmation Replicate Tests
Determining factors: Availability Cost Need Replicate Tests
Correlation of results for different characteristics of a specimen or sample
Examples: Specimen Type Specimen Condition Species / Breed Note: Correlation should be done as part of method validation. Specimen Evaluation
Where applicable evaluation of each sample should be part of ongoing quality control Specimen Evaluation
Examples: Blind or double blind control samples Development of in-house control samples Utilizing Retained Specimens
Blind or double blind control samples Examples: IHC Special Stains PCR IFA FA Etc Utilizing Retained Specimens
Considerations: Choosing samples Blind Vs double blind Accumulating results Sharing results Utilizing Retained Specimens
In-house controls and pooled In-house controls Commercial control material is not readily available Cost of commercial material is prohibitive Utilizing Retained Specimens
Confirm In-House Controls Alternate method Reference laboratory In parallel with a recognized commercial material Utilizing Retained Specimens
Participation in interlaboratory comparison or proficiency testing programs
Examples: NVSL Proficiency Test CAP Proficiency Test Interlaboratory Comparison Programs for QC Material Interlaboratory Comparisons and Proficiency Testing
Demonstrates accuracy of test method Compares accuracy of test method with peer laboratories Demonstrates competency of technical staff Interlaboratory Comparisons and Proficiency Testing
“Be a yardstick of quality. Some people aren't used to an environment where excellence is expected.” Steve Jobs (1955 - )