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📊 Quality Assurance in Diagnostic Microbiology Laboratory

A 50-Slide Presentation

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SECTION 1: INTRODUCTION & FOUNDATIONS

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Slide 1 — Title Slide

• Ensuring Accuracy, Reliability, and Patient Safety
• [Institution Name] | [Date]
• "The quality of results depends on the quality of the specimen and the techniques used to demonstrate the microbe in the sample." — Medical Microbiology 9e

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Slide 2 — Overview / Agenda

1. Foundations of QA in Microbiology
2. Regulatory Framework & Accreditation
3. Pre-Analytical Phase QA
4. Analytical Phase QA
5. Post-Analytical Phase QA
6. Quality Control (QC) Systems
7. Proficiency Testing & EQA
8. Personnel & Competency
9. Safety & Biosafety QA
10. Documentation & Records Management
11. Continuous Quality Improvement (CQI)

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Slide 3 — The Clinical Microbiology Laboratory: Its Role

• Plays a central role in the diagnosis and control of infectious diseases
• Guides antimicrobial therapy (Antimicrobial Stewardship)
• Monitors hospital-acquired infections (HAI)
• Informs public health surveillance
• Results directly impact patient outcomes

"The clinical microbiology laboratory is an integral part of an ASP, by ensuring that laboratory policies and procedures support high-quality microbiology testing and reporting." — Tietz Textbook of Laboratory Medicine, 7th Ed.

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Slide 4 — What Is Quality Assurance?

• Quality Assurance (QA): A comprehensive system of policies, procedures, and practices designed to ensure the accuracy, reliability, and timeliness of laboratory test results
• Encompasses: pre-analytical → analytical → post-analytical phases
• Distinct from Quality Control (QC):
  • QC = monitoring ongoing test performance (a subset of QA)
  • QA = the entire management system around quality

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Slide 5 — The Total Testing Process (TTP)

• Most errors occur in the pre-analytical phase (~60–70%)
• QA must address ALL three phases equally

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Slide 6 — Historical Development of Laboratory QA

• 1950s–60s: Introduction of statistical QC (Levey-Jennings charts)
• 1988: CLIA '88 (Clinical Laboratory Improvement Amendments) — US federal regulation mandating QC, PT, and competency assessment
• 1990s: ISO 9000 and ISO 15189 frameworks introduced
• 2000s: Lean and Six Sigma methodologies adopted
• Present: Risk management (ISO 22367), digital QC, real-time monitoring

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Slide 7 — Consequences of Poor QA

• False-negative cultures: Missed infections → inappropriate treatment → patient harm
• False-positive results: Unnecessary antibiotics → resistance, toxicity, cost
• Specimen mixups: Wrong result → wrong patient → serious adverse events
• Delayed reporting: Treatment delay in sepsis (mortality increases ~7%/hour)
• Regulatory consequences: Lab decertification, legal liability

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SECTION 2: REGULATORY FRAMEWORK & ACCREDITATION

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Slide 8 — Key Regulatory Bodies & Standards

"Standardized methods for clinical molecular pathologic tests are published by CLSI as guidelines on current standards of excellent practice." — Henry's Clinical Diagnosis and Management by Laboratory Methods

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Slide 9 — CLIA '88: Key Requirements for Microbiology

• Personnel standards: Director, technical supervisor, testing personnel qualifications
• Quality Control:
  • Check new reagent lots before use
  • Run positive and negative controls with each batch
  • Review and document results
• Proficiency Testing (PT): Participate in approved PT programs
• Record Retention:
  • Microbiology slides (e.g., Gram stains): 7 days
  • QC records: 5 years — Quick Compendium of Clinical Pathology, 5th Ed.

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Slide 10 — ISO 15189: Medical Laboratory Quality

• Management requirements:
  • Document control
  • Continual improvement
  • Internal audits
  • Management review
• Technical requirements:
  • Personnel competency
  • Accommodation and environment
  • Equipment calibration
  • Method validation
  • Assuring quality of results (IQC + EQA)
  • Reporting of results

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Slide 11 — CAP Accreditation in Microbiology

• Peer inspection model — labs inspect each other
• Microbiology-specific checklist includes:
  • Specimen rejection criteria
  • Incubation temperature monitoring
  • Antimicrobial susceptibility testing (AST) QC
  • Sterility of media verification
  • Biosafety practices
• CAP proficiency testing surveys include: Bacteriology, Mycobacteriology, Virology, Mycology, Parasitology, Molecular Microbiology

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Slide 12 — CLSI Guidelines for Microbiology

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SECTION 3: PRE-ANALYTICAL QA

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Slide 13 — Pre-Analytical Phase: Overview

• Pre-analytical errors account for the majority of total lab errors
• In microbiology: errors here cannot be corrected later
• Key elements:
  1. Test ordering / clinical indication
  2. Patient identification
  3. Specimen collection
  4. Transport and storage
  5. Specimen reception and processing
  6. Specimen rejection criteria

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Slide 14 — Test Ordering & Clinical Communication

• Clear clinical indication required for meaningful culture interpretation
• Common problems:
  • Inappropriate test (e.g., stool culture for hospitalized patient with C. diff)
  • Insufficient clinical information (source not specified)
  • Duplicate ordering
• QA interventions:
  • Standing order review protocols
  • Lab-clinician communication pathways
  • Reflexive testing algorithms

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Slide 15 — Patient Identification

• ALL specimens must be labeled with ≥2 patient identifiers (name + DOB or MRN)
• Unlabeled or mislabeled specimens: reject and request recollection
• Molecular labs can use DNA to resolve specimen mixups
• Barcode systems and electronic order entry reduce labeling errors

"Maintenance of connection throughout transport of the specimen to the laboratory, subsequent specimen analysis, and preparation of a report is essential." — Tietz Textbook of Laboratory Medicine, 7th Ed.

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Slide 16 — Specimen Collection: General Principles

• Specimen must be representative of the infected site
• Collected before antimicrobial therapy whenever possible
• Avoid contamination from normal flora (skin, mucous membranes)
• Use appropriate collection devices and containers
  • Sterile containers for normally sterile sites
  • Specific swabs (Amies/Stuart's transport media for bacteriology)
  • Anaerobic transport for anaerobic cultures
• Adequate volume is critical (especially blood cultures)

"The quality of results depends on the quality of the specimen collected from the patient." — Medical Microbiology 9e

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Slide 17 — Specimen Collection: Site-Specific Considerations

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Slide 18 — Specimen Transport & Storage

• Transport to the lab should be expedited — do not allow specimens to sit in collection areas
• Time-temperature guidelines:
  • Most cultures: process within 2 hours (room temp) or 24 h refrigerated
  • CSF / gonorrhea cultures: never refrigerate — maintain at 35–37°C
  • Anaerobic specimens: room temperature; dedicated anaerobic transport
  • Viral specimens: ice (4°C) or viral transport medium (VTM)

"Expedite the transport of specimens to the laboratory." — Henry's Clinical Diagnosis and Management by Laboratory Methods

• CLSI M40: Standardizes quality control of transport systems

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Slide 19 — Specimen Rejection Criteria

• Mandatory rejection (not negotiable):
  • Unlabeled or mismatched label/requisition
  • Leaking/broken container
  • Inappropriate container (e.g., urine in non-sterile bottle)
  • Specimen clearly contaminated
• Conditional rejection (contact clinician first):
  • Duplicate specimens within 24 h (e.g., 2nd sputum)
  • Inadequate volume
  • Prolonged transport time
  • Inappropriate temperature during transport
• Document ALL rejections and reasons in the LIS

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SECTION 4: ANALYTICAL PHASE QA

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Slide 20 — Analytical Phase: Overview

• Encompasses all steps from specimen receipt/processing to result generation
• QA elements:
  1. Laboratory environment and infrastructure
  2. Media and reagent quality
  3. Equipment calibration and maintenance
  4. Staining QC
  5. Antimicrobial susceptibility testing (AST) QC
  6. Molecular diagnostics QC
  7. Turnaround time (TAT) monitoring

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Slide 21 — Laboratory Environment

• Temperature monitoring:
  • Incubators: 35–37°C (aerobic), 42°C (Campylobacter), CO₂ 5–10%
  • Refrigerators: 2–8°C
  • Freezers: -20°C or -70°C (for isolates/sera)
  • Document and alarm out-of-range events
• Biosafety cabinets (BSC): Certified annually; checked before each use
• Water baths, heat blocks: Temperature verified daily
• Power backup (UPS/generator): Protects incubators and freezers

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Slide 22 — Culture Media Quality Control

• CLSI M22: QC of commercially prepared culture media
• Performance testing for each new lot/shipment:
  • Growth promotion: Positive control organisms (e.g., ATCC strains)
  • Selectivity: Negative control organisms (should be inhibited)
  • Biochemical reactivity (e.g., blood hemolysis, chromogenic reactions)
• Visual inspection: Check for contamination, color change, drying, cracks
• Storage compliance: Temp, humidity, away from light
• Expiration dates: Never use expired media

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Slide 23 — ATCC Reference Strains in QC

• ATCC strains must be subcultured from frozen stocks — not continuously passaged

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Slide 24 — Staining Quality Control

• Run QC with each staining batch or daily depending on frequency of use
• Document stain lot numbers, expiration, technologist ID

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Slide 25 — Antimicrobial Susceptibility Testing (AST) QC

• CLSI M2 (disk diffusion) and CLSI M7 (broth dilution) define QC ranges
• QC must be performed each day of testing or each week (if quality criteria met)
• Document QC results; out-of-range = investigate before reporting patient results
• Sources of AST errors:
  • Inoculum too light or too heavy
  • Incubation temperature/time out of spec
  • Disk potency expired
  • Agar pH out of range
  • Thymidine in media (trimethoprim/sulfa false resistance)
• Interpretation follows CLSI (USA) or EUCAST (Europe) breakpoints

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Slide 26 — Molecular Microbiology QA

• Most sensitive method — but prone to carryover contamination (false positives)
• Essential QC elements:
  • Internal controls (IC): Detect inhibition (false negatives)
  • Positive extraction control: Process sensitivity
  • Negative (no-template) control: Detect contamination
  • Calibrators for quantitative assays (viral loads)
• Physical separation of pre-PCR and post-PCR areas mandatory
• Method validation required before clinical use: accuracy, precision, LOD, specificity
• CLSI MM01 guidelines for molecular diagnostics

"Molecular pathology requires the same attention to quality assurance as all laboratory methods to ensure that results are accurate and reliable." — Henry's Clinical Diagnosis and Management by Laboratory Methods

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Slide 27 — Turnaround Time (TAT) Monitoring

• TAT = time from specimen receipt → result reported
• Critical in microbiology:
  • Rapid antigen tests / molecular: 1–4 hours
  • Blood cultures: Alert on positivity within hours
  • Gram stain on CSF: STAT (<1 hour)
  • Routine cultures: 24–72 hours
• QA practice:
  • Set TAT targets for each test type
  • Monitor weekly/monthly via LIS reports
  • Investigate and document outliers
  • Critical values must be called immediately (document time/recipient)

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SECTION 5: POST-ANALYTICAL QA

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Slide 28 — Post-Analytical Phase: Overview

• Often underappreciated — but errors here can be as harmful as pre-analytical errors
• Key elements:
  1. Result review and authorization
  2. Reference ranges / interpretive comments
  3. Critical value notification
  4. Report formatting and clarity
  5. Amended/corrected reports
  6. Result communication (LIS, fax, phone)

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Slide 29 — Result Review & Authorization

• All results must be reviewed before release (especially complex/critical)
• Autoverification: Automated result release if criteria are met
  • Must be validated before implementation
  • Includes delta checks, reference range, instrument flags
• Manual review triggers:
  • Unusual pathogens (e.g., B. anthracis, Y. pestis)
  • Discordant QC on batch
  • Critical/panic values
  • Mismatch between Gram stain and culture results

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Slide 30 — Critical Value / Panic Value Reporting

• Critical values in microbiology:
  • Positive blood culture Gram stain
  • CSF positive for organisms
  • Neisseria meningitidis isolated
  • Positive malaria smear
  • Detection of select agents (reportable by law)
• QA Requirements:
  • Policy defining list of critical values
  • Read-back confirmation by recipient
  • Document: time notified, person notified, by whom, read-back confirmed
  • TAT from detection to notification monitored

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Slide 31 — Interpretive Comments & Clinical Utility

• Good microbiology reports include:
  • Organisms identified to appropriate level (species if clinically relevant)
  • Quantitative results (e.g., colony counts in urine)
  • Cascade/selective reporting of antimicrobials (promotes stewardship)
  • Comments (e.g., "mixed flora — likely contamination")
  • Relevant alert flags (e.g., MRSA, ESBL, carbapenem resistance)
• Collaborate with Antimicrobial Stewardship Program (ASP)

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Slide 32 — Amended Reports & Error Correction

• Corrected report must:
  • Clearly indicate it is amended/corrected
  • State original erroneous result
  • State reason for correction
  • Be signed/authorized by laboratory director
• Notify the clinician immediately if correction changes clinical management
• Track all amended reports: frequency, reason, department — use as CQI data
• Record retention: Follow CLIA/CAP/institutional requirements

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SECTION 6: QUALITY CONTROL SYSTEMS

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Slide 33 — Internal Quality Control (IQC): Principles

• Levey-Jennings control charts: Plot QC values over time; visualize trends
• Westgard Rules: Rules for accepting/rejecting analytical runs
  • 1₂ₛ: Warning rule (1 control >2 SD)
  • 1₃ₛ: Reject if 1 control >3 SD
  • 2₂ₛ: Reject if 2 consecutive controls >2 SD same side
  • R₄ₛ: Reject if range between controls >4 SD
• In microbiology: Applied mainly to quantitative assays (viral loads, MICs)
• Qualitative tests: Use positive + negative controls daily

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Slide 34 — IQC: Practical Implementation

• QC materials should be:
  • Third-party (not manufacturer-derived) when possible
  • Matrix-appropriate (e.g., serum-based for serology)
  • Stored and used per manufacturer instructions
• Frequency:
  • Each day of testing for most culture-based tests
  • Each run for molecular assays
  • Weekly for low-frequency manual tests
• All QC failures must be documented, investigated, and resolved before patient result release

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Slide 35 — Out-of-Control Situations: Root Cause Analysis

• Do NOT release patient results from that run
• Systematic investigation:
  1. Reagent issues (new lot, expired, storage problem)?
  2. Equipment malfunction (temperature, pipetting)?
  3. Control material problem (wrong concentration, degraded)?
  4. Technologist technique (new staff, procedural deviation)?
  5. Contamination?
• Document findings, corrective action, and outcome
• If systematic error confirmed: rerun specimens from affected period

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Slide 36 — Delta Check / Trend Monitoring

• Delta check: Compares current result to previous result for same patient
  • Large unexpected change triggers review
  • Applied to quantitative microbiology (e.g., viral loads)
• Moving averages / population-based QC: Monitor reference population medians
• Trend analysis: Detect gradual instrument drift before QC limits exceeded
• These tools are standard in chemistry/hematology — increasingly applied in molecular microbiology (e.g., qPCR Ct value trending)

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SECTION 7: EXTERNAL QUALITY ASSESSMENT (EQA) & PROFICIENCY TESTING

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Slide 37 — External Quality Assessment (EQA): Principles

• EQA / Proficiency Testing (PT): An external body sends unknown samples to labs; results compared against peer labs and target values
• Also called interlaboratory comparison
• Purpose:
  • Identify systematic bias in laboratory performance
  • Benchmark against peer institutions
  • Required by CLIA, CAP, and ISO 15189
• Providers: CAP, UK NEQAS, RCPAQAP, WHO, national programs

"Interlaboratory comparison of test performance is provided by the College of American Pathologists (CAP), currently including surveys for molecular microbiology, genetics, hematology, parentage and identity, and general forensic applications." — Henry's Clinical Diagnosis and Management by Laboratory Methods

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Slide 38 — EQA in Practice: Microbiology Modules

• Unacceptable PT results: Must trigger root cause analysis, corrective action, director review

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Slide 39 — Managing PT Failures

• CLIA: Unsuccessful PT = potential sanctions, including test suspension
• Required response:
  1. Formal root cause analysis
  2. Written corrective action plan
  3. Repeat PT if available
  4. Director signature required
• Prohibited practice: Testing PT samples by a method different from routine patient testing
• PT must be rotated among testing staff (also serves as competency evidence)

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SECTION 8: PERSONNEL & COMPETENCY ASSESSMENT

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Slide 40 — Personnel Qualifications & Roles

• Ongoing training: New methods, new pathogens (e.g., emerging organisms), biosafety
• Competency must be documented at hire, after training, and annually thereafter

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Slide 41 — Competency Assessment: Six Required Elements

1. Direct observation of routine patient test performance
2. Monitoring the recording and reporting of test results
3. Review of test results/worksheets, QC records, PT results
4. Direct observation of performance of instrument maintenance and function checks
5. Assessment of test performance through testing previously analyzed specimens or PT samples
6. Evaluation of problem-solving skills

• Must be performed: 6 months after new hire, then annually
• Documentation retained as per CLIA requirements

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Slide 42 — Training for Emerging Pathogens and New Technologies

• Rapid introduction of new diagnostics: MALDI-TOF, next-generation sequencing, molecular panels
• Continuous education required:
  • In-service training
  • External CME/CE workshops
  • Manufacturer training for new instruments
• Outbreak preparedness training:
  • Response protocols for bioterrorism agents (Category A–C)
  • SARS-CoV-2 / pandemic pathogen preparedness
  • Select agent regulations
• Track training: Dates, content, sign-off by supervisor and director

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SECTION 9: SAFETY & BIOSAFETY QA

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Slide 43 — Biosafety Levels in Microbiology

• Most clinical labs: BSL-2 with BSL-3 practices for select agents
• CLSI M29: Protection of lab workers from occupationally acquired infections

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Slide 44 — Exposure Control & Safety QA

• Exposure Control Plan (per OSHA Bloodborne Pathogen Standard)
• Personal Protective Equipment (PPE) audits
• Biological spill protocols (documented, practiced)
• Sharp injury prevention: no recapping, sharps containers monitored
• Biological Safety Cabinet (BSC) certification: Annually + after relocation/filter change
• Autoclave / sterilization QC:
  • Chemical indicators (color change)
  • Biological indicators (Geobacillus stearothermophilus): Weekly or per load
• Accident/incident reporting: All exposures documented and followed up

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Slide 45 — Select Agent Program & Sentinel Laboratory QA

• Sentinel laboratory (Level A): Rules in/rules out — refers to reference lab
• Recognize and respond to potential select agents:
  • Bacillus anthracis, Yersinia pestis, Francisella tularensis, smallpox
• Laboratory Response Network (LRN) protocol:
  • Do not further characterize — contact public health
  • Package and ship per CDC/USPS regulations
  • Notify laboratory director and public health authorities
• Training in recognition: Part of competency assessment

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SECTION 10: DOCUMENTATION, RECORDS & LIS

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Slide 46 — Documentation: The Backbone of QA

• Key documents in microbiology QA:
  • Standard Operating Procedures (SOPs) — reviewed annually
  • QC records and Levey-Jennings charts
  • Equipment maintenance and calibration logs
  • Temperature logs (incubators, refrigerators, freezers)
  • Reagent and media lot records
  • Personnel training and competency records
  • PT/EQA participation and results
  • Corrective action reports
• Document control: Version control, approval signatures, change records
• CLIA record retention:
  • QC records: 5 years | Microbiology slides: 7 days | Blood bank records: 10 years

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Slide 47 — Laboratory Information System (LIS) in QA

• LIS functions critical to QA:
  • Specimen tracking (accession → result)
  • Automatic flagging of critical values
  • Delta checks
  • TAT monitoring and alerts
  • Autoverification rules
  • Interface with instruments (reduces transcription errors)
  • PT/QC data management
• LIS selection criteria include microbiology-specific modules: culture logs, sensitivity reporting, cascade reporting, epidemiology tracking

"LIS selection provides targeted evaluative criteria across multiple areas including microbiology, quality control, molecular pathology." — Henry's Clinical Diagnosis and Management by Laboratory Methods

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Slide 48 — Standard Operating Procedures (SOPs)

• SOPs must include:
  • Principle of test
  • Specimen requirements
  • Reagents/equipment
  • Step-by-step procedure
  • QC requirements
  • Expected results / interpretive criteria
  • Reference ranges
  • Limitations
  • References (e.g., CLSI guidelines)
• Review cycle: Annual review and re-authorization by director
• Accessible to all testing personnel (paper or electronic)
• Deviations from SOPs: Documented and investigated

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SECTION 11: CONTINUOUS QUALITY IMPROVEMENT

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Slide 49 — Continuous Quality Improvement (CQI) Tools

• PDCA Cycle (Plan-Do-Check-Act): Core framework for CQI
• Root Cause Analysis (RCA): Deep dive into why failures occur
• FMEA (Failure Mode and Effects Analysis): Proactive risk identification
• Lean / Six Sigma: Eliminate waste, reduce variation
  • DMAIC: Define-Measure-Analyze-Improve-Control
• Key Quality Indicators (KQIs) for microbiology:
  • Specimen rejection rate
  • Blood culture contamination rate (<3%)
  • TAT for critical specimens
  • PT pass rate (100% target)
  • Amended report rate
  • Unscheduled instrument downtime

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Slide 50 — Summary & Key Takeaways

"Appropriate specimen collection, transport, and processing are the critical first steps to quality results." — Henry's Clinical Diagnosis and Management by Laboratory Methods

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📚 References

1. Henry's Clinical Diagnosis and Management by Laboratory Methods, 23rd Ed. — McPherson & Pincus (Elsevier, 2021)
2. Medical Microbiology, 9th Ed. — Murray et al. (Elsevier, 2021)
3. Tietz Textbook of Laboratory Medicine, 7th Ed. — Rifai et al. (Elsevier, 2023)
4. Quick Compendium of Clinical Pathology, 5th Ed. (ASCP, 2020)
5. Sherris & Ryan's Medical Microbiology, 8th Ed. (McGraw-Hill, 2022)
6. CLSI Standards: M2, M7, M11, M22, M29, M40, M47, MM01
7. CLIA '88 Regulations (42 CFR Part 493)
8. ISO 15189:2022 — Medical Laboratories Requirements for Quality and Competence
9. CAP Laboratory Accreditation Program Checklists---

Presentation Summary

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Quality Assurance in Diagnostic Microbiology Laboratory

Based on: Ananthanarayan & Paniker | Bailey & Scott | Koneman's Color Atlas | CLSI Standards

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SECTION 1: INTRODUCTION & FOUNDATIONS

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Slide 1 — Title Slide

• Principles and Practice
• Sources: Ananthanarayan & Paniker's Textbook of Microbiology | Bailey & Scott's Diagnostic Microbiology | Koneman's Color Atlas and Textbook of Diagnostic Microbiology | CLSI Standards

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Slide 2 — What Is Quality Assurance?

Quality Assurance (QA): "An all-encompassing program that guarantees the quality of laboratory test results through careful control of all the variables that can affect the accuracy and precision of test results."

QA is: "A program designed to ensure that results issued by the laboratory are correct and that the laboratory functions in an efficient and cost-effective manner."

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Slide 3 — Total Quality Management (TQM) in Microbiology

• QA = umbrella management system
• QC = subset — monitoring test performance
• Continuous Quality Improvement (CQI) = ongoing refinement
• Three pillars:
  1. Structure — physical lab, equipment, personnel
  2. Process — specimen handling, testing methods, reporting
  3. Outcome — accuracy of results, patient outcomes, TAT

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Slide 4 — The Three Phases: Total Testing Process

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Slide 5 — The Microbiology Lab and Infectious Disease Diagnosis

• Isolation and identification of causative microorganisms
• Antimicrobial susceptibility testing
• Serological diagnosis (antibody/antigen detection)
• Molecular diagnosis (NAATs)
• Epidemiological surveillance and outbreak investigation

"The diagnosis of an infectious disease depends on the isolation and identification of the causative organism or the detection of specific antibodies in the patient's serum." — Ananthanarayan & Paniker

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Slide 6 — Regulatory & Accreditation Framework

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SECTION 2: PRE-ANALYTICAL QA

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Slide 7 — Pre-Analytical Phase: Overview

• A contaminated or improperly collected specimen yields misleading results
• No amount of technical excellence in the lab can compensate for a poor specimen

"The single most important step in the recovery of microorganisms from clinical specimens is the proper collection of the specimen." — Bailey & Scott's Diagnostic Microbiology

• Test request / clinical information
• Patient preparation
• Specimen collection technique
• Labeling and identification
• Transport and storage
• Receipt and processing

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Slide 8 — Specimen Request and Clinical Information

• Patient name and date of birth / hospital ID
• Type of specimen and anatomical site
• Date and time of collection
• Name of ordering physician and contact
• Clinical diagnosis / relevant history
• Current antimicrobial therapy (affects culture sensitivity)
• Type of test requested

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Slide 9 — Specimen Collection: General Principles

1. Collect from the actual site of infection — not adjacent normal flora
2. Collect during acute phase of illness
3. Collect adequate quantity
4. Collect before starting antimicrobials whenever possible
5. Use appropriate sterile technique to avoid contamination
6. Use correct collection devices (swabs, aspirates, tissue)
7. Use appropriate transport media immediately after collection
8. Label clearly and transport promptly

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Slide 10 — Site-Specific Collection Requirements

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Slide 11 — Blood Culture Collection: QA Specifics

• Number: 2–3 sets per episode (increases sensitivity to >95%)
• Volume: 8–10 mL per bottle in adults; 1–3 mL pediatric
• Timing: Before antibiotics; within 30–60 min of each other during acute fever
• Antisepsis: 70% isopropanol → 2% chlorhexidine or tincture of iodine — allow to dry
• QA indicator: Blood culture contamination rate — target <3% (CAP/CLSI benchmark)
• Common contaminants: Coagulase-negative Staphylococci, Bacillus, Corynebacterium, Propionibacterium

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Slide 12 — Sputum Quality Criteria: Bartlett Scoring

• Gram stain screen is mandatory before culture
• Murray-Washington / Bartlett grading:

"A predominance of squamous epithelial cells indicates oropharyngeal contamination, and the specimen should be rejected." — Bailey & Scott

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Slide 13 — Transport Media and Systems

• Prevent desiccation
• Maintain pH
• Inhibit overgrowth of normal flora
• Preserve viability of fastidious organisms

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Slide 14 — Time-Temperature Requirements for Transport

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Slide 15 — Specimen Rejection Criteria

• Unlabeled or mismatched label/requisition
• Container leaking, broken, or grossly contaminated
• Incorrect fixative (e.g., formalin for culture)
• 24-hour urine for culture
• Multiple swabs when one was required

• Sputum with >25 squamous epithelial cells/lpf
• Duplicate wound cultures within 24 h
• Rectal swab (if stool possible)
• Prolonged transport time or wrong temperature

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SECTION 3: CULTURE MEDIA QUALITY CONTROL

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Slide 16 — Culture Media in Diagnostic Microbiology

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Slide 17 — CLSI M22: QC of Culture Media

1. Visual inspection: Color, turbidity, hemolysis, contamination, cracks, moisture
2. pH verification: Acceptable range ±0.2 pH units of stated value
3. Sterility check: Incubate uninoculated plates/tubes at 35°C × 24–48 h — no growth
4. Growth promotion (positive control): Inoculate with ATCC reference strain — adequate growth expected
5. Selectivity (negative control): Inoculate with organism that should be inhibited — no/limited growth expected
6. Biochemical reactivity: Correct biochemical reactions observed

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Slide 18 — QC Organisms for Common Media

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Slide 19 — Media Storage and Shelf Life

• Refrigerated media (2–8°C): Most agar plates, prepared broths
• Room temperature: Thioglycollate broth (do not refrigerate)
• Protect from light (especially chocolate agar, thio broth)
• Shelf life:
  • Commercially prepared plates: Follow manufacturer expiry
  • In-house prepared: Typically 2 weeks refrigerated
  • Dehydrated media (powder): 2–5 years in sealed containers at room temp
• Never use expired media — document lot number and expiry for every batch

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Slide 20 — Preparation of In-House Media: QA Checks

1. Weigh dehydrated medium accurately (record batch weight)
2. Dissolve in measured volume of distilled water
3. Check/adjust pH (before autoclaving for most; after for blood-containing)
4. Autoclave at 121°C, 15 psi, 15 minutes (record autoclave run)
5. Cool to 50–55°C before adding blood/supplements
6. Pour into sterile plates/tubes under sterile conditions
7. QC: Visual inspection + pH + sterility + growth promotion before use
8. Label: Medium name, lot, date prepared, expiry, technologist initials

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SECTION 4: STAINING QUALITY CONTROL

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Slide 21 — Gram Stain QC

• Run positive and negative controls with each batch of staining
• QC organisms (on same slide or separate):
  • Staphylococcus aureus → gram-positive cocci (purple)
  • Escherichia coli → gram-negative rods (red/pink)

"A good Gram stain distinguishes bacterial morphology and gram reaction and is directly correlated with culture results." — Koneman

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Slide 22 — Other Stain QC

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SECTION 5: ANTIMICROBIAL SUSCEPTIBILITY TESTING (AST) QC

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Slide 23 — AST Methods and Standards

"The disk diffusion method, as described by Bauer, Kirby, Sherris, and Turck, remains the most widely used test for determining antimicrobial susceptibility." — Koneman

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Slide 24 — Kirby-Bauer Disk Diffusion: QC

• Mueller-Hinton agar:
  • Depth: 4 mm ± 0.5 mm
  • pH: 7.2–7.4
  • Free of thymidine (interferes with sulfonamides/trimethoprim)
  • Divalent cations (Ca²⁺, Mg²⁺) within range
• Inoculum: 0.5 McFarland standard (1–2 × 10⁸ CFU/mL)
• Disk potency: Store at -20°C (carbapenem, clavulanate-containing); 4°C for others
• Incubation: 35–37°C, 16–18 h; 24 h for staphylococci/oxacillin/vancomycin

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Slide 25 — AST QC Organisms and Acceptable Ranges

• QC must be performed each day of testing (or weekly if QC criteria met per CLSI M02)
• Results plotted on Levey-Jennings chart to detect trends

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Slide 26 — AST Interpretation: Breakpoints and Reporting

• S (Susceptible): Infection likely to respond to standard dosing
• I (Intermediate): Uncertain — may respond to higher dose or concentrated site
• R (Resistant): Unlikely to respond to standard therapy
• SDD (Susceptible-Dose Dependent): Response dependent on achieving high drug levels

• Use cascade/selective reporting to promote antibiotic stewardship
• Report ESBL, carbapenemase, MRSA flags prominently
• Confirm by additional testing when resistance is unexpected (e.g., vancomycin-resistant S. aureus)

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SECTION 6: INTERNAL QUALITY CONTROL (IQC)

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Slide 27 — Principles of IQC

• Day-to-day reproducibility of test results
• Instrument performance and reagent consistency
• Technologist technique

"Controls should be treated exactly as patient specimens — same preparation, same technologist, same instrument." — Koneman

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Slide 28 — Levey-Jennings Charts and Westgard Rules

• Plot control values (Y-axis) vs. time/run (X-axis)
• Draw lines at mean ± 1SD, ±2SD, ±3SD
• Visual identification of random vs systematic error

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Slide 29 — Out-of-Control: Response Protocol

1. Stop: Do NOT report patient results from that run
2. Check controls: Wrong concentration? Degraded? Wrong storage?
3. Check reagents: Expired? New lot? Stored correctly?
4. Check equipment: Temperature? Pipettes calibrated? Correct incubation?
5. Check technique: New analyst? Procedural deviation?
6. Check for contamination: Environmental contamination?
7. Repeat QC with fresh controls
8. If QC passes → release results; document findings and corrective action
9. If repeated failure → escalate to supervisor/director; hold patient results
10. Root cause analysis and corrective action plan documented

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SECTION 7: EXTERNAL QUALITY ASSESSMENT (EQA)

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Slide 30 — EQA / Proficiency Testing: Principles

External Quality Assessment (EQA) / Proficiency Testing (PT): "A system for objectively checking laboratory performance by means of interlaboratory comparisons, using external samples of known composition."

• Independent validation that the lab's methods are working correctly
• Identifies bias, systematic errors, or performance gaps
• Required for laboratory accreditation (NABL, CAP, ISO 15189, CLIA)
• Benchmarks the lab against peer institutions nationally/internationally

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Slide 31 — EQA in Practice

1. External body (CAP, EQAS, RCPAQAP, UK NEQAS, national programs) sends unknown samples
2. Lab processes them exactly as patient specimens — same methods, same personnel
3. Results submitted to provider
4. Performance compared against target value and peer group
5. Report returned: graded acceptable / unacceptable

• Bacteriology: Organism identification + AST
• Mycobacteriology: Smear microscopy + culture identification
• Mycology: Yeast/mould identification
• Parasitology: Stool examination, smear reading
• Serology: Antibody titers
• Molecular: NAAT detection / quantification

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Slide 32 — Managing EQA Failures

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SECTION 8: EQUIPMENT QC AND MAINTENANCE

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Slide 33 — Laboratory Equipment: QC Requirements

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Slide 34 — Autoclave QC: Sterilization Assurance

1. Physical indicators: Built-in gauges (temperature, pressure, time) — recorded each run
2. Chemical indicators (CI):
   • Bowie-Dick test strips: Color change confirms steam penetration
   • Class 5/6 integrating indicators inside packs
3. Biological indicators (BI):
   • Geobacillus stearothermophilus spore strips
   • Most resistant to moist heat (121°C)
   • Run weekly or per load for critical cycles
   • No growth after incubation = sterilization confirmed

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Slide 35 — Biosafety Cabinet (BSC) QC

• Annual certification by qualified engineer (NSF/ANSI 49)
• Before each use: Check airflow alarm, UV light (if fitted), wipe-down with 70% alcohol
• HEPA filter replacement: Per manufacturer schedule or when airflow compromised
• Decontamination before servicing: Formaldehyde or vaporized hydrogen peroxide

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SECTION 9: PERSONNEL AND COMPETENCY

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Slide 36 — Personnel Requirements

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Slide 37 — Competency Assessment

1. Direct observation of specimen processing and testing
2. Monitoring of recording and reporting of results
3. Review of QC records and PT results
4. Direct observation of equipment maintenance
5. Assessment of problem-solving skills (e.g., evaluate written unknowns)
6. Testing of previously analyzed samples / EQA specimens

• Initial: After completion of training (before independent testing)
• 6-month reassessment: During first year
• Annual: Every year thereafter

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Slide 38 — Training in the Microbiology Laboratory

• Standard Operating Procedures (SOPs) for all tests performed
• Specimen handling, collection, and rejection criteria
• Gram staining technique and interpretation
• Culture reading, colonial morphology, preliminary identification
• AST performance and interpretation (Kirby-Bauer, MIC)
• QC procedures and documentation
• Biosafety (BSL-2 practices, PPE, spill management)
• Bloodborne pathogen training (OSHA standard)
• Fire safety, chemical hygiene, emergency procedures
• LIS operation and result entry/verification

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SECTION 10: SAFETY QA IN MICROBIOLOGY

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Slide 39 — Biosafety Levels

"Most clinical specimens should be handled using Universal (Standard) Precautions as a minimum." — Koneman

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Slide 40 — Standard Precautions and PPE

• Treat ALL specimens as potentially infectious
• Mandatory PPE in microbiology:
  • Gloves: Change between specimens; remove before leaving lab
  • Lab coat: Not worn outside the lab
  • Eye protection/face shield: During specimen processing, centrifugation
  • Mask/respirator: N95 for suspected AFB specimens (BSL-3 practices)
• No: Eating, drinking, mouth pipetting, applying cosmetics in the lab
• Wash hands: After removing gloves, before leaving the lab

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Slide 41 — Exposure Control and Incident Reporting

• Needlestick/sharps injury:
  1. Wash immediately with soap and water
  2. Report to supervisor and occupational health
  3. Baseline serology (HIV, HBV, HCV)
  4. Post-exposure prophylaxis (PEP) if indicated within 2–4 h
• Spill management:
  • Small spill (BSL-2): Cover with paper towel + 10% bleach; 20 min contact; clean up; decontaminate
  • Large spill or BSL-3: Evacuate; notify supervisor; wait for trained decontamination team
• All exposures documented: Date, nature, circumstances, follow-up actions

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SECTION 11: DOCUMENTATION AND LIS

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Slide 42 — SOPs: Structure and Management

• CLSI QMS02: "Quality Management System — Development and Management of Laboratory Documents"
• Required sections in an SOP:
  1. Title, SOP number, version, effective date
  2. Purpose and clinical relevance
  3. Principle of the test
  4. Specimen requirements (type, volume, container, storage)
  5. Equipment and reagents (with lot tracking)
  6. Step-by-step procedure
  7. QC requirements and acceptance criteria
  8. Interpretation of results / reference criteria
  9. Reporting instructions
  10. Limitations and interferences
  11. Safety precautions
  12. References (CLSI, manufacturer IFU)
  13. Authorization signatures (author, reviewer, director)

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Slide 43 — Document Control

• Each SOP has a unique identifier and version number
• Annual review and re-authorization — even if no changes
• Only current version accessible to staff — obsolete versions removed from circulation
• Master list of all SOPs maintained by QA coordinator
• Changes documented with reason, date, and authorized signature
• Controlled copies distributed; uncontrolled copies marked as such
• LIS or electronic document management systems preferred for access control

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Slide 44 — Record Keeping

• Documents: Procedures, policies, forms (written before the fact)
• Records: Evidence that activities were performed (written after the fact)

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Slide 45 — Laboratory Information System (LIS) in QA

• Unique accession number for every specimen (audit trail)
• Patient identification verification (wristband scan / barcode)
• Specimen rejection logging with reason codes
• Automated culture workload and TAT tracking
• AST reporting with cascade/selective reporting logic
• Critical value flagging with call-back documentation
• Trend monitoring and epidemiology reports (antibiograms)
• Interface with blood culture instruments (automated alert on positivity)
• PT/QC data management and charting
• Authorized result release (autoverification with rules)

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SECTION 12: SPECIAL AREAS OF MICROBIOLOGY QA

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Slide 46 — Mycobacteriology QA

• BSL-3 practices for all culture work
• Three sputum specimens: Early morning, on 3 consecutive days
• Smear microscopy QC:
  • Positive control slide with known AFB+ case
  • Negative control slide
  • Two-microscopist reading for discrepant results (WHO recommendation)
• Culture media QC (LJ, MGIT):
  • M. tuberculosis H37Rv ATCC 27294
  • Sterility check of each batch
• Grading smears (WHO / Ananthanarayan):
  • Negative: 0 AFB / 100 fields
  • Scanty: 1–9 AFB / 100 fields (report exact count)
  • 1+: 10–99 AFB / 100 fields
  • 2+: 1–10 AFB / field (>50 fields)
  • 3+: >10 AFB / field (>20 fields)

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Slide 47 — Molecular Microbiology QA

• Zone 1: Master mix preparation (pre-PCR, ultra-clean)
• Zone 2: Specimen extraction and nucleic acid addition
• Zone 3: Amplification and detection (post-PCR)
• Unidirectional workflow only — no backflow

• Accuracy, precision, analytical sensitivity (LOD), specificity, interfering substances

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Slide 48 — Blood Culture System QA

• Instrument maintenance: Daily flag review, quarterly preventive maintenance
• Bottle integrity: Inspect for cracks, leaks, incorrect fill before incubation
• Blood culture contamination rate: Monitor monthly; target <3%
• Positive bottle Gram stain: STAT critical value — call clinician within defined TAT
• Subculture from positive bottles: Blind subculture at 12 h for some systems

1. Prepare Gram stain from positive bottle
2. Call result to physician/nurse (critical value) — document
3. Set up blood agar + chocolate agar + MacConkey subcultures
4. Consider direct sensitivity testing from positive bottle broth

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SECTION 13: QUALITY INDICATORS AND CQI

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Slide 49 — Key Quality Indicators (KQIs) for Microbiology

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Slide 50 — CQI Cycle and Summary

  PLAN  →  Identify problem using KQIs and data
            Set measurable improvement targets
     ↓
   DO   →  Implement intervention
            Train staff; modify procedure or workflow
     ↓
 CHECK  →  Measure outcome against target
            Re-audit; compare KQIs before/after
     ↓
   ACT  →  Standardize if improved
            If not improved → go back to PLAN

1. Specimens: Right patient, right site, right container, right time
2. Media & Reagents: Verified, documented, within expiry
3. Methods: Standardized per CLSI; controlled with ATCC organisms
4. Personnel: Trained, competent, assessed
5. Equipment: Calibrated, maintained, monitored
6. Documentation: Comprehensive, current, retrievable
7. EQA: Regular participation; failure triggers RCA
8. Safety: Biosafety integrated into every procedure
9. CQI: Data-driven, continuous, director-led

"Quality in the microbiology laboratory is not optional — it is the foundation upon which every clinical decision rests."

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References for This Presentation

1. Ananthanarayan R & Paniker CKJ — Textbook of Microbiology, 10th Ed. (Orient Longman)
2. Bailey & Scott — Diagnostic Microbiology, 14th Ed., Forbes BA, Sahm DF, Weissfeld AS (Elsevier Mosby)
3. Koneman EW et al. — Koneman's Color Atlas and Textbook of Diagnostic Microbiology, 7th Ed. (Wolters Kluwer/Lippincott)
4. CLSI M02 — Performance Standards for Antimicrobial Disk Susceptibility Tests
5. CLSI M07 — Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria
6. CLSI M11 — Methods for Antimicrobial Susceptibility Testing of Anaerobic Bacteria
7. CLSI M22 — Quality Assurance for Commercially Prepared Microbiological Culture Media
8. CLSI M29 — Protection of Laboratory Workers from Occupationally Acquired Infections
9. CLSI M40 — Quality Control of Microbiological Transport Systems
10. CLSI M47 — Principles and Procedures for Blood Cultures
11. CLSI M100 — Performance Standards for Antimicrobial Susceptibility Testing (updated annually)
12. CLSI MM01 — Molecular Diagnostic Methods for Infectious Diseases
13. CLSI QMS01, QMS02, QMS03, QMS05, QMS12, QMS24 — Quality Management System series
14. CLSI EP15, EP23 — User verification; risk management in the lab

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