Determining Causative Laboratory Error in Bioburden, Endotoxin, and Environmental Monitoring OOS Results

In the previous post, we discussed the critical importance of thorough investigations into deviations, as highlighted by the recent FDA warning letter to Sanofi. Let us delve deeper into a specific aspect of these investigations: determining whether an invalidated out-of-specification (OOS) result for bioburden, endotoxin, or environmental monitoring action limit excursions conclusively demonstrates causative laboratory error.

When faced with an OOS result in microbiological testing, it’s crucial to conduct a thorough investigation before invalidating the result. The FDA expects companies to provide scientific justification and evidence that conclusively demonstrates a causative laboratory error if a result is to be invalidated.

Key Steps in Evaluating Laboratory Error

1. Review of Test Method and Procedure

Examine the standard operating procedure (SOP) for the test method
Verify that all steps were followed correctly
Check for any deviations from the established procedure

2. Evaluation of Equipment and Materials

Evaluation of Equipment and Materials is a critical step in determining whether laboratory error caused an out-of-specification (OOS) result, particularly for bioburden, endotoxin, or environmental monitoring tests. Here’s a detailed approach to performing this evaluation:

Equipment Assessment

Functionality Check

Run performance verification tests on key equipment used in the analysis
Review equipment logs for any recent malfunctions or irregularities
Verify that all equipment settings were correct for the specific test performed

Calibration Review

Check calibration records to ensure equipment was within its calibration period
Verify that calibration standards used were traceable and not expired
Review any recent calibration data for trends or shifts

Maintenance Evaluation

Examine maintenance logs for adherence to scheduled maintenance
Look for any recent repairs or adjustments that could affect performance
Verify that all preventive maintenance tasks were completed as required

Materials Evaluation

Reagent Quality Control

Check expiration dates of all reagents used in the test
Review storage conditions to ensure reagents were stored properly
Verify that quality control checks were performed on reagents before use

Media Assessment (for Bioburden and Environmental Monitoring)

Review growth promotion test results for culture media
Check pH and sterility of prepared media
Verify that media was stored at the correct temperature

Water Quality (for Endotoxin Testing)

Review records of water quality used for reagent preparation
Check for any recent changes in water purification systems
Verify endotoxin levels in water used for testing

Environmental Factors

Laboratory Conditions

Review temperature and humidity logs for the testing area
Check for any unusual events (e.g., power outages, HVAC issues) around the time of testing
Verify that environmental conditions met the requirements for the test method

Contamination Control

Examine cleaning logs for the laboratory area and equipment
Review recent environmental monitoring results for the testing area
Check for any breaches in aseptic technique during testing

Documentation Review

Standard Operating Procedures (SOPs)

Verify that the most current version of the SOP was used
Check for any recent changes to the SOP that might affect the test
Ensure all steps in the SOP were followed and documented

Equipment and Material Certifications

Review certificates of analysis for critical reagents and standards
Check equipment qualification documents (IQ/OQ/PQ) for compliance
Verify that all required certifications were current at the time of testing

By thoroughly evaluating equipment and materials using these detailed steps, laboratories can more conclusively determine whether an OOS result was due to laboratory error or represents a true product quality issue. This comprehensive approach helps ensure the integrity of microbiological testing and supports robust quality control in pharmaceutical manufacturing.

3. Assessment of Analyst Performance

Here are key aspects to consider when evaluating analyst performance during an OOS investigation:

Review Training Records

Examine the analyst’s training documentation to ensure they are qualified to perform the specific test method.
Verify that the analyst has completed all required periodic refresher training.
Check if the analyst has demonstrated proficiency in the particular test method recently.

Evaluate Recent Performance History

Review the analyst’s performance on similar tests over the past few months.
Look for any patterns or trends in the analyst’s results, such as consistently high or low readings.
Compare the analyst’s results with those of other analysts performing the same tests.

Conduct Interviews

Interview the analyst who performed the test to gather detailed information about the testing process.
Ask open-ended questions to encourage the analyst to describe any unusual occurrences or deviations from standard procedures.
Inquire about the analyst’s workload and any potential distractions during testing.

Observe Technique

If possible, have the analyst demonstrate the test method while being observed by a supervisor or senior analyst.
Pay attention to the analyst’s technique, including sample handling, reagent preparation, and equipment operation.
Note any deviations from standard operating procedures (SOPs) or good practices.

Review Documentation Practices

Examine the analyst’s laboratory notebooks and test records for completeness and accuracy.
Verify that all required information was recorded contemporaneously.
Check for any unusual notations or corrections in the documentation.

Assess Knowledge of Method and Equipment

Quiz the analyst on critical aspects of the test method and equipment operation.
Verify their understanding of acceptance criteria, potential sources of error, and troubleshooting procedures.
Ensure the analyst is aware of recent changes to SOPs or equipment calibration requirements.

Evaluate Workload and Environment

Consider the analyst’s workload at the time of testing, including any time pressures or competing priorities.
Assess the laboratory environment for potential distractions or interruptions that could have affected performance.
Review any recent changes in the analyst’s responsibilities or work schedule.

Perform Comparative Testing

Have another qualified analyst repeat the test using the same sample and equipment, if possible.
Compare the results to determine if there are significant discrepancies between analysts.
If discrepancies exist, investigate potential reasons for the differences.

Review Equipment Use Records

Check equipment logbooks to verify proper use and any noted issues during the time of testing.
Confirm that the analyst used the correct equipment and that it was properly calibrated and maintained.

Consider Human Factors

Assess any personal factors that could have affected the analyst’s performance, such as fatigue, illness, or personal stress.
Review the analyst’s work schedule leading up to the OOS result for any unusual patterns or extended hours.

By thoroughly assessing analyst performance using these methods, investigators can determine whether human error contributed to the OOS result and identify areas for improvement in training, procedures, or work environment. It’s important to approach this assessment objectively and supportively, focusing on systemic improvements rather than individual blame.

4. Examination of Environmental Factors

Review environmental monitoring data for the testing area
Check for any unusual events or conditions that could have affected the test

5. Data Analysis and Trending

Compare the OOS result with historical data and trends
Look for any patterns or anomalies that might explain the result

Conclusive vs. Inconclusive Evidence

Conclusive Evidence of Laboratory Error

To conclusively demonstrate laboratory error, you should be able to:

Identify a specific, documented error in the testing process
Reproduce the error and show how it leads to the OOS result
Demonstrate that correcting the error leads to an in-specification result

Examples of conclusive evidence might include:

Documented use of an expired reagent
Verified malfunction of testing equipment
Confirmed contamination of a negative control

Inconclusive Evidence

If the investigation reveals potential issues but cannot definitively link them to the OOS result, the evidence is considered inconclusive. This might include:

Minor deviations from SOPs that don’t clearly impact the result
Slight variations in environmental conditions
Analyst performance issues that aren’t directly tied to the specific test

Special Considerations for Microbiological Testing

Bioburden, endotoxin, and environmental monitoring tests present unique challenges due to their biological nature.

Bioburden Testing

Consider the possibility of sample contamination during collection or processing
Evaluate the recovery efficiency of the test method
Assess the potential for microbial growth during sample storage

Endotoxin Testing

Review the sample preparation process, including any dilution steps
Evaluate the potential for endotoxin masking or enhancement
Consider the impact of product formulation on the test method

Environmental Monitoring

Assess the sampling technique and equipment used
Consider the potential for transient environmental contamination
Evaluate the impact of recent cleaning or maintenance activities

Documenting the Investigation

Regardless of the outcome, it’s crucial to thoroughly document the investigation process. This documentation should include:

A clear description of the OOS result and initial observations
Detailed accounts of all investigative steps taken
Raw data and analytical results from the investigation
A comprehensive analysis of the evidence
A scientifically justified conclusion

Conclusion

Determining whether an invalidated OOS result conclusively demonstrates causative laboratory error requires a systematic, thorough, and well-documented investigation. For microbiological tests like bioburden, endotoxin, and environmental monitoring, this process can be particularly challenging due to the complex and sometimes variable nature of biological systems.

Remember, the goal is not to simply invalidate OOS results, but to understand the root cause and implement corrective and preventive actions. Only through rigorous investigation and continuous improvement can we ensure the quality and safety of pharmaceutical products. When investigating environmental and in-process results we are investigating the whole house of contamination control.

Failure to Investigate Critical Deviations: A Cautionary Tale from Sanofi’s FDA Warning Letter

The recent FDA warning letter issued to Sanofi on January 15, 2025 highlights a critical issue that continues to plague pharmaceutical manufacturers – inadequate investigation of deviations. Specifically, the FDA cited Sanofi for “failure to thoroughly investigate any unexplained discrepancy or failure of a batch or any of its components to meet any of its specifications, whether or not the batch has already been distributed.”

This observation underscores the importance of robust deviation investigation and CAPA (Corrective and Preventive Action) systems.

The Importance of Thorough Investigations

Investigating deviations is not just a regulatory requirement – it’s a critical part of ensuring product quality and patient safety. The objective of an investigation is not merely to perform the investigation, but to improve the reliability of our manufacturing operations, the ultimate objective being increased quality and availability of those regulated healthcare products.

When companies fail to thoroughly investigate deviations, they miss opportunities to:

Identify root causes of quality issues
Implement effective corrective actions
Prevent recurrence of similar problems
Improve overall manufacturing processes and controls

Common Pitfalls in Deviation Investigations

Some common reasons why deviation investigations fall short include:

Lack of trained, competent investigators
Inadequate time and resources allocated to investigations
Pressure to close investigations quickly
Failure to look beyond the immediate symptoms to identify true root causes
Over-reliance on “human error” as a root cause
Poor documentation of investigation activities and rationale

Building Better Investigation and CAPA Processes

To overcome these challenges and build more effective investigation and CAPA systems, companies should consider the following approaches:

1. Develop Investigator Competencies

Having competent investigators is crucial. Companies should:

Define required competencies for investigators
Provide comprehensive training on investigation techniques and tools
Implement mentoring programs for new investigators
Regularly assess and refresh investigator skills

2. Implement a Risk-Based Approach

Not all deviations require the same level of investigation. Using a risk-based approach allows companies to:

Prioritize critical deviations for in-depth investigation
Allocate appropriate resources based on potential impact
Ensure thorough investigations for high-risk issues

3. Use Structured Investigation Methods

Adopting structured investigation methods helps ensure consistency and thoroughness. Some useful tools include:

Fishbone diagrams for brainstorming potential causes
Why-Why analysis for drilling down to root causes
Fault tree analysis for complex issues
Timeline analysis to understand the sequence of events

4. Look Beyond Human Error

Human error is not a root cause. Instead of stopping at “operator error”, investigators should dig deeper to understand:

Why the error occurred
What system or process factors contributed to the error
How similar errors can be prevented in the future

5. Improve Documentation Practices

Thorough documentation is essential for demonstrating the adequacy of investigations to regulators. Key elements include:

Clear description of the deviation
Investigation steps taken
Data and evidence collected
Root cause analysis
Rationale for conclusions
Corrective and preventive actions

6. Implement Effective CAPAs

The investigation is only the first step – implementing effective corrective and preventive actions is crucial. Companies should:

Ensure CAPAs directly address identified root causes
Consider both short-term corrections and long-term preventive measures
Assess potential risks of proposed CAPAs
Establish clear timelines and accountability for CAPA implementation
Conduct effectiveness checks to verify CAPA impact

7. Foster a Culture of Quality

Management plays a critical role in creating an environment that supports thorough investigations.

Providing adequate time and resources for investigations
Encouraging open reporting of deviations without fear of blame
Recognizing and rewarding thorough investigation practices
Leading by example in prioritizing quality and patient safety

Common Pitfalls in Investigating Microbiological Contamination Events

When investigating microbiological contamination events there are often several pitfalls that can hinder the effectiveness of their investigations.

Inadequate Root Cause Analysis

One of the most significant pitfalls is failing to conduct a thorough root cause analysis. Investigators may be tempted to attribute contamination to superficial causes like “human error” without digging deeper into systemic issues. This shallow approach often leads to ineffective corrective actions that fail to prevent recurrence. Build in safeguards to avoid jumping to conclusion.

Overlooking Environmental Factors

Investigators sometimes neglect to consider the broader environmental context of contamination events. Factors such as air handling systems, water quality, and even compressed air can harbor contaminants. Failing to examine these potential sources may result in missed opportunities for identifying the true origin of contamination.

Insufficient Microbial Identification

Relying solely on phenotypic identification methods can lead to misidentification of contaminants. Phenotypic results can incorrectly point to laboratory contamination, while genotypic testing revealed a production-related issue. Using a combination of identification methods, including genotypic techniques, can provide more accurate and actionable results.

Premature Conclusion of Investigations

Pressure to close investigations quickly can lead to premature conclusions. This was evident in the Sanofi warning letter, where the FDA noted that investigations into critical deviations, including multiple microbiological contamination events, were inadequate. Rushing the process can result in overlooking important details and failing to implement effective corrective actions.

Failure to Consider Cross-Contamination

Investigators may not always consider the possibility of cross-contamination between products or areas within the facility. The presence of drug-resistant microbial contaminants, as observed in some studies, underscores the importance of examining potential routes of transmission and implementing strict hygiene procedures.

Inadequate Documentation

Poor documentation of investigation activities and rationale can undermine the credibility of findings and make it difficult to justify conclusions to regulators. The FDA’s warning letter to Sanofi highlighted this issue, noting that not all investigational activities were documented.

Neglecting Trending and Data Analysis

Failing to analyze contamination events in the context of historical data and trends can lead to missed patterns and recurring issues. Establishing and maintaining a comprehensive microflora database is essential for effective contamination control strategies and can provide valuable insights for investigations.

Insufficient Training of Investigators

Lack of properly trained and competent investigators can significantly impact the quality of contamination investigations. Ensuring that personnel have the necessary skills and knowledge to conduct thorough, science-based investigations is crucial for identifying true root causes and implementing effective corrective actions.

Conclusion

The Sanofi warning letter serves as a reminder of the critical importance of thorough deviation investigations in pharmaceutical manufacturing. By implementing robust investigation and CAPA processes, companies can not only avoid regulatory action but also drive continuous improvement in their operations. This requires ongoing commitment to developing investigator competencies, using structured methods, looking beyond superficial causes, and fostering a culture that values quality and learning from deviations.

As the industry continues to evolve, effective investigation practices will be essential for ensuring product quality, patient safety, and regulatory compliance. By viewing deviations not as failures but as opportunities for improvement, pharmaceutical manufacturers can build more resilient and reliable production systems.

OOS failures

Go and read the January 2021 FDA warning letter to Allay Pharmaceuticals and then go and read the 1993 decision in United States vs Barr Laboratories.

The Barr decision, issued 28 years ago, explains how to deal with OOS results. The FDA followed up with a guidance in 2006 “Guidance for Industry Investigating Out-of-Specification (OOS) Test Results for Pharmaceutical Production.” Companies have no excuse for continued failure here, and yet as we see with Allay (and so many others) failures in investigation of out-of-specifications continues to be a major concern. Yet nothing we see is not covered in the Barr decision.

If you a pharmaceutical GMP professional these three documents should be ones you are more than ready to explain against your quality system.