Week Two Tutorial

Week Two Tutorial Overview

  • Focus on External Quality Assurance (EQA)

Importance of EQA

  • A critical quality assurance measure in laboratory settings
  • Relevant for method verification projects
    • Understanding EQA can help identify issues with BCG assays

Definition of External Quality Assurance

  • Definition: A system designed to objectively assess the quality of laboratory results through an external agency.
  • Major providers of EQA in Australia:
    • RCPA QAP (Royal College of Pathologists Australasia Quality Assurance Program)
  • Other global providers:
    • Bio-Rad
    • Randox
  • Use of EQA is not mandatory for all labs but is highly recommended.

Requirement for Enrollment in EQA Programs

  • Mandatory enrollment for all assays that have an available EQA program
    • Essential for patient safety and clinical accountability
    • Necessary for compliance with regulatory bodies (e.g., NADA and Medicare payments)

Role of EQA in Quality Management

  • Complementary to internal quality control measures
  • Provides a measure of long-term accuracy and performance of laboratory methods
  • Offers a perspective on precision of assays
    • Allows identification of method performance issues
    • Provides educational benefits for laboratory staff
  • Quantification of quality when true values are unknown via consensus or field values

EQA Program Features

  • Sponsored by professional societies like RCPA and AACB
  • Laboratory participation:
    • Analyze specimens regularly based on program cycles
    • Chemistry programs may require processing 12 to 18 samples per cycle
  • Submission of results:
    • Results submitted via online portal
    • Reports include data analysis, statistical summaries, and plots

Sample Processing in EQA Programs

  • EQA samples may be received pre-made (lyophilized or frozen) and must be reconstituted as specified prior to analysis
    • Cycle for EQA:
    1. Receive EQA samples at beginning of year
    2. Analyze samples within recommended timeframes
    3. Submit results by cutoff dates to be included in data analysis
  • Immediate performance assessment and long-term performance statistics provided back to laboratories

Analysis of EQA Samples

  • EQA provides validation independently of internal QC programs
  • Samples treated as patient samples for accurate process evaluation
  • System must not differentiate between EQA and patient sample treatment protocols to ensure comprehensive assessment of laboratory functions
  • Sample matrix considerations:
    • Samples should ideally match patient sample matrices (e.g., human serum or CSF) to avoid matrix effects

Identifying Accuracy Problems through EQA

  • Accuracy problems identified through significant deviation from target values, assessed relative to peers and definitive/reference methods
  • Performance specifications called Analytical Performance Specifications (APS) and Allowable Limits Performance (ALP) used for assessing results
  • APS serves as a standard for quality control in terms of clinical significance

Understanding and Interpreting EQA Reports

  • Reports consist of:
    • Analyte names and units
    • Sample and cycle information
    • Method classifications
    • Performance measures (APS)
  • Data visualizations include:
    • Histograms
    • Euden plots (low vs. high concentration samples)
    • Levy Jennings style plots
    • Linearity graphs for assessing method linearity

Example of EQA Report Elements

  1. Analyte name
  2. Units of measurement
  3. Results submitted by the lab
  4. Method classification
  5. APS limits
  6. Histograms: Compare lab results to peer performance
  7. Euden Plots: Visual representation of results from similar methods
  8. Levy Jennings Style Plot: Evaluates deviation trends over time
  9. Linearity Graph: Shows deviations from target values by level of analyte concentration

Troubleshooting EQA Issues

  • Guidelines on steps to take when issues arise with EQA results
  • Example Scenario 1: BNP assay results with significant deviation from consensus indicates potential reporting errors.
  • Example Scenario 2: Alkaline phosphatase results show systematic bias across multiple assays, leading to the conclusion of incorrect methods or sample processing requiring further investigation into reconstitution protocols
  • Lab must investigate peers for comparative context, review daily QC data, and ensure adherence to EQA methods to avoid bias

Practical Component for Week Two

  • Focus on diagnosis and monitoring of diabetes with patient Mr. Sukhamanathong
  • Tests to be performed:
    1. Fasting Glucose: Manual analysis using glucose oxidase method.
    2. Fructosamine: Using Roche COBAS analyzer.
    3. HbA1c: Using Affinion device for point of care testing.

Quality Control Considerations

  • Two levels of quality control for each manual and automated analyte
  • Documentation of QC results, including Z-scores, and compliance with Westgard rules for qualitative assessment and patient result reporting

Reviewing EQA Report Elements for Method Verification

  • Students to familiarize themselves with EQA reports and identify potential issues within BCG albumin assays
    • Assess bias and the significance for patient care

Conclusion

  • Emphasize the importance of EQA as part of quality assurance in laboratory settings and its impact on clinical decision-making.
  • Encourage ongoing study and understanding of EQA processes, reports, and implications for patient safety and treatment accuracy.