SOP For Handling of Microbiological Data Deviation (MDD) in Microbiology Laboratory
1.0 Objective
1.1 To lay down a systematic procedure for identification, reporting, investigation, evaluation, and closure of Microbiological Data Deviations (MDD) observed in the Microbiology Laboratory.
2.0 Scope
2.1 This SOP is applicable to all microbiological deviations arising from the following activities:
- Environmental Monitoring (Passive Air Sampling, Active Air Sampling, Surface Monitoring, Personnel Monitoring, Compressed Gas Monitoring)
- Sterility Testing
- Bacterial Endotoxin Test (BET)
- Bioburden Testing
- Microbial Limit Test (MLT)
- Liquid Borne Particulate Matter Test
- Antimicrobial Effectiveness Testing (AET)
- Container Closure Integrity (CCI) Tests
- Water Samples (WFI, Purified Water, and Utility Water Systems)
- Total Organic Carbon (TOC) Testing
3.0 Responsibility
3.1 Microbiologist
- Implementation of this SOP
- Immediate reporting of deviations
- Conducting primary laboratory investigation
3.2 Head – Microbiology / Designee
- Conduct detailed laboratory investigation
- Ensure compliance with this SOP
- Conclude laboratory findings
3.3 QA Executive / Designee
- Assign Microbiological Data Deviation (MDD) number
- Ensure tracking and documentation
3.4 IPQA Executive / Designee
- Conduct investigation in manufacturing area
3.5 Head – Production / Designee
- Provide manufacturing-related support during investigation
3.6 Head – Engineering / Designee
- Investigate engineering-related causes (HVAC, utilities, WFI, compressed gases)
3.7 Head – Quality Assurance
- Review and approve investigation reports
- Ensure implementation of CAPA
4.0 Accountability
4.1 Head – Quality Control shall be accountable for overall compliance with this SOP.
5.0 Procedure
5.1 Definitions
5.1.1 Laboratory Error:
An error occurring during testing due to procedural deviation, calculation error, dilution error, equipment malfunction, or analyst error.
5.1.2 Assignable Cause:
Scientifically justified and documented reason for deviation identified during investigation.
5.1.3 Alert Limit:
A warning limit indicating potential process drift requiring investigation but not necessarily corrective action. Three alert excursions within a week in a specific area shall be treated as an Action Limit excursion.
5.1.4 Action Limit:
A limit indicating loss of process control requiring documented investigation and corrective actions. Product impact evaluation is mandatory, especially in Grade A areas.
5.1.5 Negative Control:
Control used to identify false-positive results.
5.1.6 Positive Product Control (PPC):
Test sample spiked with known endotoxin concentration for inhibition verification.
5.1.7 Resample:
Additional sample collected following approved sampling procedure.
5.1.8 Lambda (λ):
Labeled lysate sensitivity in gel clot endotoxin assay.
5.2 Logging and Initial Investigation of MDD
5.2.1 Any microbiological deviation shall be immediately reported to Head–Microbiology.
5.2.2 QA shall assign MDD number in the format:
MDD/YY/XX
- MDD – Microbiological Data Deviation
- YY – Year
- XX – Serial Number
5.2.3 All MDDs shall be recorded in the MDD Log Book.
5.2.4 Laboratory investigation shall begin promptly without preconceived conclusions.
5.2.5 Investigation shall include:
- Review of raw data
- Review of analyst qualification and training
- Equipment calibration/qualification
- Environmental conditions
- Media and reagent status
- Abnormal incidents during testing
5.3 Environmental Monitoring Excursions
5.3.1 Alert Limit Excursion
- Log MDD.
- Notify Production and QA within one working day.
- Conduct investigation using approved checklist.
- Review HVAC parameters (Temperature, RH, DP, air changes).
- Review entry logs and personnel practices.
- Provide retraining if required.
- Observe trend of next day’s results.
- Three alerts in one week shall be treated as Action Limit.
If excursion occurs in critical area, review sterility results of associated batches.
5.3.2 Action Limit Excursion
- Log MDD and notify QA and Production.
- Stop production and hold batches.
- Perform cleaning, disinfection, fumigation.
- Conduct monitoring for three consecutive satisfactory days.
- Identify isolates (species level).
- Evaluate:
- Type of isolate
- Critical vs non-critical site
- Repeated trend
- Airborne vs surface contamination
- Review HVAC and HEPA integrity.
- Conduct additional sampling if required.
- Submit report to QA.
- Release batches only after satisfactory conclusion.
- In case of product contact surface contamination during manufacturing, batch rejection shall be considered.
All investigations must be completed within 30 days.
5.4 Bacterial Endotoxin Test (BET) Failure Investigation
Investigation shall be conducted in two phases.
Phase I – Laboratory Investigation
- Review negative controls and PPC.
- Check reagent validity and sensitivity (±2λ).
- Verify depyrogenation records.
- Check instrument calibration.
- Review analyst qualification.
- Review other samples tested simultaneously.
If laboratory error identified:
- QA authorizes resampling.
- Retest in triplicate by another qualified analyst.
- If all pass → invalidate MDD and implement CAPA.
If failure persists → escalate to Phase II.
Phase II – Manufacturing Investigation
Investigation team:
- Head QA
- Head Production
- Head Microbiology
Review:
- BMR
- Water endotoxin results
- Equipment cleaning/depyrogenation
- Raw material endotoxin results
- Environmental data (1 month)
If assignable cause found → reject batch.
If no cause found → retest at another qualified unit.
If failure confirmed → reject batch.
5.4.7 Exceeded Endotoxin in WFI
- Immediately stop WFI usage.
- Inform QA, Engineering, Production.
- Resample user points and return loop.
- Perform triplicate testing.
- Conduct corrective actions.
- Resume only after 3 consecutive satisfactory days.
5.5 Microbial Limit Test (MLT) / Bioburden Failure
Phase I – Laboratory Review:
- Media quality and GPT
- Sterilization records
- Equipment qualification
- Environmental data
- Calculation verification
- Isolate identification (species level)
If lab error confirmed:
- Invalidate test
- Retest in triplicate
- Implement CAPA
If no lab error:
- Extend to Phase II manufacturing investigation
5.6 Liquid Borne Particulate Matter Failure
Phase I:
- Document review
- Equipment qualification
- Analyst review
If no assignable cause → Phase II investigation including Production and Engineering.
Retest at alternate unit if required.
5.7 Sterility Failure Investigation
5.7.1 Immediately report and log MDD.
5.7.2 Stop production and place related batches on HOLD.
5.7.3 Identify isolate up to species level.
5.7.4 Preserve isolate (2–8°C).
Laboratory Investigation:
- Review sterility test procedure
- Review sterilization records
- Review EM data
- Review personnel monitoring
- Review media and controls
- Correlate isolate with EM history
If laboratory error confirmed → invalidate and retest with QA approval.
If not → reject batch and extend to manufacturing.
Manufacturing Investigation:
Review:
- Sterilization of equipment
- Cleaning records
- HVAC validation
- EM trend (6 months)
- Media fill history
- Filter integrity
- Compressed gas analysis
- WFI data
- Personnel monitoring
- Raw material sterility history
If confirmed sterility failure:
- Reject batch
- Sanitize facility
- Conduct 3 consecutive successful media fills before restart.
Investigation shall be completed within 30 working days.
5.8 Water Sample Failure Investigation
Alert Limit:
- Log MDD
- Investigate pipelines, valves, filters
- Monitor closely
Action Limit:
- Stop usage
- Inform QA, Engineering, Production
- Perform sanitization
- Resample for 3 consecutive days
- Restart only after compliance
TOC Exceedance
- Follow same Alert and Action approach
- Resample return loop
- Restart only after satisfactory results
5.9 Antimicrobial Effectiveness Test (AET)
Due to complexity and variability:
Invalid Test:
- Document invalidity
- Repeat new valid test
Putative Failure:
- Perform two independent confirmatory AETs
- If either fails → confirmed failure
Root Cause Analysis:
- Identify cause
- Implement CAPA
- Evaluate effectiveness
6.0 Time Frame
All MDD investigations shall be completed within 30 working days from detection. Extension requires documented justification and QA approval.
7.0 Annexures
- MDD Log Book
- Excursion Notification Format
- Environmental Monitoring Checklist
- BET Investigation Format
- MLT/Bioburden Investigation Format
- Particulate Matter Investigation Format
- Sterility Failure Notification
- Sterility Lab Investigation Checklist
- Manufacturing Investigation Checklist (Sterility)
- Water Failure Investigation Report
SOP on Container Closure Integrity Testing (CCIT) for Dry Powder for Injection