External Quality Assessment Scheme (EQAS) failures can be challenging for laboratories, necessitating thorough investigation to identify root causes and implement corrective actions. This article outlines the steps to investigate EQAS failures, focusing on where to look, how to find the root cause, methodologies for investigation, and tools for analysis, with a case example provided for illustration.
Understanding EQAS Failures
EQAS failures occur when laboratory test results deviate from the expected range in external proficiency testing. These deviations can stem from various factors, including technical issues, operator errors, and environmental conditions. Investigating these failures involves a systematic approach to pinpoint the root cause and prevent recurrence.
Step-by-Step Investigation Process
- Initial Assessment and Documentation
- Review EQAS Report: Examine the EQAS report to identify specific tests that failed and the extent of deviation.
- Document Findings: Record all relevant details, including test methods, reagents, equipment, and personnel involved.
- Gathering Information
- Collect Data: Gather all relevant data, such as quality control (QC) logs, calibration records, and maintenance schedules.
- Interview Staff: Talk to personnel involved in the testing process to understand any procedural anomalies or deviations.
- Identifying Potential Causes
- Technical Factors: Investigate equipment calibration, reagent quality, and testing procedures.
- Environmental Factors: Assess storage conditions for reagents and samples, including temperature and humidity.
- Operator Factors: Evaluate staff training, adherence to protocols, and consistency in test execution.
- Root Cause Analysis (RCA)
- Methodology: Employ RCA tools such as Fishbone Diagrams, 5 Whys, and Failure Mode and Effects Analysis (FMEA) to systematically explore potential causes.
- Case Study Analysis: Use specific cases to illustrate how these tools can identify underlying issues.
Case Example: Bilirubin EQAS Failure in Dry Chemistry
Context
A laboratory experienced EQAS failures in biochemical tests for Bilirubin, Alkaline Phosphatase (Alk Phos), and Serum Glutamic-Oxaloacetic Transaminase (SGOT) using dry chemistry techniques. The failures were associated with the dry chemistry method.
Investigation Process
- Initial Assessment
- The EQAS report indicated significant deviations in Bilirubin results.
- Data Collection
- QC logs revealed inconsistent Bilirubin readings over the past month.
- Calibration records showed the analyzer had not been calibrated in the last two months.
- Potential Causes Identified
- Technical Factors: Reagent strip instability, inconsistent sample application, and light exposure during testing.
- Environmental Factors: Storage conditions for reagent strips were not consistently monitored.
- Operator Factors: Variability in sample application techniques among different operators.
- Root Cause Analysis
- Fishbone Diagram: Illustrated potential causes such as reagent quality, storage conditions, operator technique, and equipment calibration.
- 5 Whys Analysis: Drilled down to identify that inconsistent storage conditions led to reagent strip degradation.
Findings and Corrective Actions
Bilirubin
Root Cause: Reagent strip instability due to improper storage conditions and light exposure during testing.
Corrective Actions:
- Store reagent strips under recommended conditions, avoiding exposure to heat, humidity, and light.
- Standardize sample application techniques across all operators.
- Conduct all testing in a consistently lit environment.
Alkaline Phosphatase (Alk Phos)
Root Cause: Calibration drift and lot-to-lot variability of test strips.
Corrective Actions:
- Regularly calibrate the analyzer using standard calibration tools.
- Validate each new lot of strips using control materials before use.
SGOT (AST)
Root Cause: Substrate degradation on test strips and instrument reading variability.
Corrective Actions:
- Ensure substrate reagents are not expired and stored properly.
- Perform routine maintenance and calibration checks on the analyzer.
Tools for Analyzing EQAS Failures
- Fishbone Diagram (Ishikawa)
- Helps identify and categorize potential causes of failures.
- 5 Whys Analysis
- Aids in drilling down to the root cause by repeatedly asking “why” for each identified issue.
- Failure Mode and Effects Analysis (FMEA)
- Assesses potential failure modes, their causes, and effects to prioritize corrective actions.
Conclusion
Investigating EQAS failures involves a detailed and systematic approach to uncover root causes and implement effective corrective actions. By employing tools such as Fishbone Diagrams, 5 Whys, and FMEA, laboratories can enhance their diagnostic accuracy and reliability. The case of Bilirubin EQAS failure in dry chemistry exemplifies the importance of addressing technical, environmental, and operator-related factors to improve overall test performance and quality assurance.
CASE STUDY :
Investigating Bilirubin EQAS Failure: A Step-by-Step Analysis Using 5 Whys and FMEA
Introduction
This section provides a detailed roadmap for investigating Bilirubin EQAS (External Quality Assessment Scheme) failures using real data and employing the 5 Whys and Failure Mode and Effects Analysis (FMEA) methodologies. This comprehensive guide will help laboratories follow a structured approach to root cause analysis and implement corrective actions.
Step-by-Step Investigation Process
1. Initial Assessment and Documentation
EQAS Report Findings:
- Bilirubin test results significantly deviated from the expected range.
- The reported Bilirubin value was 18 mg/dL, while the expected range was 0.2-1.2 mg/dL.
Document Findings:
- Test Method: Dry chemistry technique.
- Reagents: Reagent strips.
- Equipment: Dry chemistry analyzer.
- Personnel: Three operators were involved in the testing process.
2. Gathering Information
Collect Data:
- QC logs for Bilirubin tests over the past three months.
- Calibration records for the dry chemistry analyzer.
- Maintenance schedules for the equipment.
- Storage conditions for reagent strips.
Interview Staff:
- Gather insights from the operators on their testing procedures and any observed anomalies.
3. Identifying Potential Causes
Technical Factors:
- Reagent strip quality and stability.
- Calibration status of the analyzer.
- Consistency in sample application techniques.
Environmental Factors:
- Storage conditions (temperature and humidity) for reagent strips.
- Light exposure during testing.
Operator Factors:
- Variability in handling and applying samples.
- Training and adherence to protocols.
5 Whys Analysis
Problem: Bilirubin EQAS failure with reported value significantly higher than expected.
- Why was the Bilirubin value 18 mg/dL?
- Because the reagent strip gave an incorrect high reading.
- Why did the reagent strip give an incorrect high reading?
- Because the reagent strip was degraded.
- Why was the reagent strip degraded?
- Because it was exposed to high humidity and improper storage conditions.
- Why was the reagent strip exposed to high humidity and improper storage conditions?
- Because the storage area did not have adequate humidity control and monitoring.
- Why did the storage area lack adequate humidity control and monitoring?
- Because the laboratory did not implement environmental controls for reagent storage as per manufacturer guidelines.
Root Cause: Inadequate storage conditions leading to reagent strip degradation.
Failure Mode and Effects Analysis (FMEA)
Purpose: To systematically analyze potential failure modes, their causes, and effects, and to prioritize corrective actions.
FMEA Table for Bilirubin EQAS Failure
| Failure Mode | Potential Effects | Potential Causes | Current Controls | Severity (1-10) | Occurrence (1-10) | Detection (1-10) | Risk Priority Number (RPN) | Actions |
| High Bilirubin reading | Incorrect patient diagnosis | Degraded reagent strips | Periodic QC checks | 9 | 7 | 6 | 378 | Implement strict storage controls |
| Calibration drift | Systematic error in results | Irregular calibration | Monthly calibration | 8 | 6 | 5 | 240 | Increase calibration frequency |
| Sample application inconsistency | Variability in results | Operator technique | Operator training | 7 | 5 | 4 | 140 | Standardize sample application |
Actions and Corrective Measures:
- Implement Strict Storage Controls:
- Action: Install humidity control devices in the storage area and monitor conditions regularly.
- Responsible: Lab Manager.
- Timeline: Immediate implementation.
- Follow-up: Weekly checks on storage conditions.
- Increase Calibration Frequency:
- Action: Calibrate the dry chemistry analyzer bi-weekly instead of monthly.
- Responsible: Quality Control Technician.
- Timeline: Start from the next calibration cycle.
- Follow-up: Review calibration logs bi-weekly.
- Standardize Sample Application:
- Action: Develop and enforce a standardized protocol for sample application across all operators.
- Responsible: Lab Supervisor.
- Timeline: Within one month.
- Follow-up: Conduct training sessions and audits.
Conclusion
The investigation into the Bilirubin EQAS failure using the 5 Whys and FMEA methodologies revealed that the primary root cause was inadequate storage conditions leading to reagent strip degradation. By implementing strict storage controls, increasing calibration frequency, and standardizing sample application techniques, the laboratory can significantly reduce the risk of future EQAS failures. This structured approach not only resolves the immediate issue but also enhances overall laboratory quality management, ensuring reliable and accurate test results.
Case Summary
Initial Problem: Bilirubin EQAS failure with reported value significantly higher than expected.
Root Cause: Inadequate storage conditions leading to reagent strip degradation.
Corrective Actions:
- Implement strict humidity and temperature controls for reagent storage.
- Increase the frequency of equipment calibration.
- Standardize and train operators on sample application techniques.
By following this roadmap, laboratories can effectively investigate and resolve EQAS failures, ensuring high standards of accuracy and reliability in their testing processes.
About the Author
Dr. Sambhu Chakraborty is a distinguished consultant in quality accreditation for laboratories and hospitals. With a leadership portfolio that includes directorial roles in two laboratory organizations and a consulting firm, as well as chairman of International Organization of Laboratories ( An ILAC stakeholder organisation), Dr. Chakraborty is a respected voice in the field. For further engagement or inquiries, Dr. Chakraborty can be contacted through email at info@sambhuchakraborty.com and contact information are available on his websites,https://www.quality-pathshala.com and https://www.sambhuchakraborty.com , or via WhatsApp at +91983005158