Auditing microbiology laboratory MCQs With Answer

Introduction: This quiz collection on auditing microbiology laboratories is designed specifically for M.Pharm students preparing for advanced coursework and professional examinations. It addresses critical areas of laboratory audits such as regulatory requirements (GMP, ISO and pharmacopeial standards), environmental monitoring, sterility assurance, microbiological methods validation, sampling plans, documentation and deviation handling. Questions focus on practical audit observations, interpretation of data, risk-based decision making, and corrective/preventive actions. Working through these MCQs will sharpen your ability to identify nonconformities, assess microbiological control strategies, and prepare robust audit reports—skills essential for quality assurance roles in pharmaceutical microbiology.

Q1. Which document provides the primary regulatory expectations for sterile medicinal product manufacture in the European Union relevant to microbiology laboratory audits?

• ICH Q9: Quality Risk Management
• EU GMP Annex 1: Manufacture of Sterile Medicinal Products
• ISO 13485: Medical Devices — Quality Management Systems
• USP General Chapter <1116> Microbiological Control and Monitoring of Aseptic Processing Environments

Correct Answer: EU GMP Annex 1: Manufacture of Sterile Medicinal Products

Q2. During an audit, an auditor finds that environmental monitoring data shows occasional airborne recoveries above the alert level but within action level. The best immediate audit observation is:

• Ignore, because results are within action level
• Recommend recalibration of monitoring equipment
• Assess trends, investigate root causes, and review CAPA if necessary
• Shut down production immediately

Correct Answer: Assess trends, investigate root causes, and review CAPA if necessary

Q3. Which parameter is most critical to verify during a media fill audit of aseptic operations?

• Incubation temperature accuracy for media used in process simulation
• Adequacy of nutrient formulation for patient safety
• Operator gowning color coordination
• Batch record numbering format

Correct Answer: Incubation temperature accuracy for media used in process simulation

Q4. In a microbiology lab audit, what does an Out-of-Specification (OOS) result require the auditor to evaluate?

• Only the laboratory analyst who performed the test
• Investigation of method performance, sampling, equipment, personnel, and documentation
• Immediate discard of all related product lots without investigation
• Automatic re-test without documented rationale

Correct Answer: Investigation of method performance, sampling, equipment, personnel, and documentation

Q5. Which of the following is a key element of a robust environmental monitoring program for microbiology labs?

• Sampling only during off-shift hours
• Use of a single sampling method for all areas and media
• Defined sampling locations, frequencies, alert/action limits, and trend analysis
• Recording results informally in personal notebooks

Correct Answer: Defined sampling locations, frequencies, alert/action limits, and trend analysis

Q6. When auditing sterility testing, which aspect most directly ensures sample integrity before testing?

• Color of the sample container cap
• Chain of custody, appropriate storage conditions, and aseptic sampling technique
• Brand of incubator used
• Number of analysts available on that day

Correct Answer: Chain of custody, appropriate storage conditions, and aseptic sampling technique

Q7. Which regulatory or guidance document specifically addresses cleanroom microbial contamination control and terminology used in biotech/pharmaceutical industries?

• FDA Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing
• ISO 14698: Cleanrooms and associated controlled environments — Biocontamination control
• ICH Q7: Good Manufacturing Practice for Active Pharmaceutical Ingredients
• OECD GLP Principles

Correct Answer: ISO 14698: Cleanrooms and associated controlled environments — Biocontamination control

Q8. An auditor reviews a microbiology lab method validation. Which element indicates the method is appropriately validated for microbial enumeration?

• Validation only reports analyst names and signatures
• Demonstrated accuracy, precision, specificity, detection limit, and robustness for intended use
• Use of expired media during validation
• Validation performed on a single replicate

Correct Answer: Demonstrated accuracy, precision, specificity, detection limit, and robustness for intended use

Q9. In auditing water for injection (WFI) microbiological control, the auditor should expect:

• No monitoring because WFI is sterile by definition
• Routine microbial counts, endotoxin testing, and validated sanitization of distribution loop
• Only visual inspection of pipelines
• Monitoring only once per year

Correct Answer: Routine microbial counts, endotoxin testing, and validated sanitization of distribution loop

Q10. What is the appropriate auditor action when finding repeated failure to incubate sterility test plates at the specified temperature?

• Document as minor observation and close audit
• Recommend immediate corrective action, review affected results, and assess impact on product release
• Ignore because incubation failures are common
• Switch to alternative methods without documentation

Correct Answer: Recommend immediate corrective action, review affected results, and assess impact on product release

Q11. Which statistical concept is most relevant when auditors evaluate microbial environmental monitoring trends?

• Randomized block design
• Use of control charts and trend analysis to detect shifts from baseline
• ANOVA for color variance
• Kaplan–Meier survival curves

Correct Answer: Use of control charts and trend analysis to detect shifts from baseline

Q12. During an audit of sample handling, an auditor discovers that numerous samples were left at room temperature for extended periods before testing. The auditor should:

• Recommend immediate discard of all affected samples without investigation
• Evaluate sample stability data, assess impact on results, and require a documented investigation
• Assume results are still valid because the lab is experienced
• Require only re-training of staff with no documentation

Correct Answer: Evaluate sample stability data, assess impact on results, and require a documented investigation

Q13. Which element in a microbiology lab audit demonstrates compliance with data integrity principles?

• Handwritten corrections without initials or dates
• Secure audit trails for electronic systems, controlled access, and legible, attributable records
• Multiple untracked copies of raw data in different locations
• Deleting outlier colony counts without documentation

Correct Answer: Secure audit trails for electronic systems, controlled access, and legible, attributable records

Q14. For endotoxin (LAL) testing audits, which control is crucial to ensure test validity?

• Using only one lot of water for all tests
• Use of positive product controls (spike recovery) and appropriate negative controls to detect inhibition/enhancement
• Relying solely on historical endotoxin trends
• Skipping validation for products with preservatives

Correct Answer: Use of positive product controls (spike recovery) and appropriate negative controls to detect inhibition/enhancement

Q15. Which observation in a microbiology audit specifically indicates a problem with personal practices rather than facility or equipment?

• Visible dust on HEPA inlet grills
• Operators touching critical surfaces with gloved hands during aseptic operations
• Incorrect calibration sticker on incubator
• Damaged sampling port seals

Correct Answer: Operators touching critical surfaces with gloved hands during aseptic operations

Q16. What is the significance of action and alert limits in environmental monitoring as assessed by an auditor?

• They are recommended values with no need for response
• Alert limits prompt investigation and trending; action limits require immediate investigation and corrective action
• They refer only to temperature and humidity
• They are used solely for lab personnel performance reviews

Correct Answer: Alert limits prompt investigation and trending; action limits require immediate investigation and corrective action

Q17. When auditing a microbiology lab’s equipment qualification, which documentation should be available to demonstrate suitability for intended use?

• Only a purchase invoice
• Installation Qualification (IQ), Operational Qualification (OQ), and Performance Qualification (PQ)
• Verbal assurance from maintenance staff
• Unqualified warranty documents

Correct Answer: Installation Qualification (IQ), Operational Qualification (OQ), and Performance Qualification (PQ)

Q18. An auditor is reviewing corrective and preventive action (CAPA) records after a contamination event. Which element indicates an effective CAPA?

• CAPA closed without verification or follow-up
• Root cause documented, corrective actions implemented, effectiveness verified with metrics and trend improvement
• CAPA focused only on disciplinary action
• Repetition of the same action for all incidents regardless of cause

Correct Answer: Root cause documented, corrective actions implemented, effectiveness verified with metrics and trend improvement

Q19. In a microbiology audit, which practice would raise concern about the reliability of microbial enumeration results?

• Use of validated, expiry-tracked culture media and growth promotion testing
• Inconsistent plate count methods (changing diluents, volumes, or dilutions without justification)
• Regular proficiency testing of analysts
• Controlled incubator temperature logs

Correct Answer: Inconsistent plate count methods (changing diluents, volumes, or dilutions without justification)

Q20. Which audit finding suggests inadequate control of contamination sources in a microbiology laboratory?

• Documented segregation of dirty and clean zones with clear signage
• High counts on non-viable particle monitoring coinciding with increases in viable recoveries
• Routine use of appropriate disinfectants and contact times
• Scheduled HEPA filter maintenance with records

Correct Answer: High counts on non-viable particle monitoring coinciding with increases in viable recoveries

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