Quality Control David Korcal BSMT ASCP What is

Quality Control David Korcal, BSMT, (ASCP)

What is Quality Control? The monitoring of results obtained from the performance of a standard operating procedure • Test results • Results obtained from a process

“Quality has to be caused, not controlled. ” Philip Crosby, Reflections on Quality

AAVLD Essential Requirements 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: a) b) c) d) e) f) 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.

The laboratory shall have procedures for monitoring the validity of test results. This monitoring shall be planned and reviewed … • 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

Choose the appropriate Quality Control Methods Where applicable: • Use appropriate statistics • Use recognized standard control material • Replicate test • Consider specimen evaluation • Utilizing retained specimens • Inter-laboratory comparison • Proficiency testing

Internal Quality Control Schemes Using Statistical Techniques

Where applicable monitor using appropriate statistics Quantitative assays: Examples: • • • Glucose, Serum Platelet Count Total T 4 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

Veterinary Diagnostic Laboratory QC. Form. 007. 01 Canine Direct Coombs Quality Control Log Date Positive Control Lot Expected Results: Positive Control Result Negative Control Lot (Positive) Negative Control Result Initials Comments (Negative) 10/1/2007 K 9 P 2007 Positive K 9 N 2007 Negative MB 10/2/2007 K 9 P 2007 Positive K 9 N 2007 Negative CF 10/3/2007 K 9 P 2007 Positive K 9 N 2007 Negative CF 10/4/2007 K 9 P 2007 Positive K 9 N 2007 Negative CF 10/5/2007 K 9 P 2007 Positive K 9 N 2007 Negative CF 10/6/2007 K 9 P 2007 Positive K 9 N 2007 Negative MB 10/8/2007 K 9 P 2007 Positive K 9 N 2007 Negative MB 10/9/2007 K 9 P 2007 Positive K 9 N 2007 Negative MB 10/10/2007 K 9 P 2007 Positive K 9 N 2007 Negative MB 10/11/2007 K 9 P 2007 Negative K 9 N 2007 Negative TL 10/11/2007 K 9 P 2007 Positive K 9 N 2007 Negative MB Assay Repeated by MB

Where applicable, use of international reference reagents for preparation of national and/or working standards for internal quality control

Use recognized standard control material 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

When practical, replicate tests using the same or different methods

Replicate Tests 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

Correlation of results for different characteristics of a specimen or sample

Specimen Evaluation 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

Re-testing of retained specimens or samples

Utilizing Retained Specimens 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 • Etc

Utilizing Retained Specimens Considerations: • • Choosing samples Blind Vs double blind Accumulating results Sharing results

Utilizing Retained Specimens In-house controls and pooled Inhouse 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

Participation in interlaboratory comparison or proficiency testing programs

Interlaboratory Comparisons and Proficiency Testing 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

“Be a yardstick of quality. Some people aren't used to an environment where excellence is expected. ” Steve Jobs (1955 - )