Microbiology Quality Control: Essential Practices for Reliable Culture Results

Microbiology quality control (QC) is the system of checks, tests, and documentation that confirms laboratory media, reagents, equipment, and personnel performance produce accurate and reproducible culture results. For laboratory students, technicians, researchers, and diagnostic professionals, QC is not an administrative afterthought. It is the operational backbone that determines whether an isolate identification, an antimicrobial susceptibility result, or a negative culture report can be trusted for patient management, outbreak investigation, or research conclusions. This article defines the core QC practices for a microbiology laboratory, explains how to implement them in daily workflow, and describes the specific responsibilities of QC personnel.

Quality assurance (QA) in the clinical microbiology laboratory refers to the quality control activities related to analytical procedures, and QA should include both external and internal quality assessment [6]. External quality control supports laboratory intercomparisons, detection of random and systematic errors, evaluation of reagent or commercial kit suitability, and continuing education [6]. Internal quality control detects random and systematic errors through inclusion of quality control samples in assays, equipment monitoring, and audit [6]. Evaluation of all assays before inclusion in daily routine work is of utmost importance [6].

The scope of microbiology QC extends beyond the analytical phase. Preanalytical and postanalytical factors have considerable impact on quality, yet performance assessment and improvement in these areas have received less consideration than analytical quality control [10]. A total testing process approach includes interdisciplinary participation, specimen quality, test use, result use, turnaround time, information quality, user perceptions, and benchmarking [10].

At a Glance

Core Principles of Microbiology Quality Control

The Total Testing Process

Quality management in clinical microbiology must address the entire testing pathway, also the analytical step. The preanalytical phase includes specimen collection, transport, and receipt. The analytical phase includes culture setup, incubation, identification, and susceptibility testing. The postanalytical phase includes result reporting, interpretation, and communication to clinicians [10]. Each phase carries distinct QC requirements and failure modes.

Specimen quality is a preanalytical QC concern. A culture result is only as reliable as the specimen from which it was derived. Laboratories should track rejection rates for improperly collected, mislabeled, or delayed specimens and provide feedback to collection sites. Test use and result use are also QC concerns. A laboratory can produce technically perfect results that are clinically useless if the wrong test was ordered or the result is reported in a format that is not actionable [10].

Internal and External Quality Assessment

Internal quality control involves the daily or batch-based checks performed within the laboratory. These include testing known control organisms alongside patient specimens, monitoring equipment performance, and auditing procedures [6]. Internal QC detects problems as they occur and allows corrective action before unreliable results are released.

External quality assessment involves sending specimens or data to an external program for interlaboratory comparison. External QC detects random and systematic errors, evaluates the suitability of reagents or commercial diagnostic kits, and supports continuing education [6]. Participation in an external quality assessment program is a standard expectation for accredited clinical laboratories. A Taiwan-based quality assurance program demonstrated that proficiency test specimens sent to all participating laboratories twice a year, with approximately three specimens per evaluation, produced tremendous improvements in laboratory performance quality [12].

Manufacturer Responsibility and Laboratory Verification

Quality control in microbiology has largely passed into the hands of the manufacturer with the proliferation and widespread usage of commercial identification systems [8]. Commercial systems undergo manufacturer validation, but the laboratory retains responsibility for verifying that each new lot performs as expected in the local setting. The validity, precision, and specificity of commercially available systems and individual methods for identification of bacteria, yeasts, and bacterial antigens, as well as blood culture systems, must be assessed [8].

The laboratory must verify manufacturer claims under its own conditions. This includes testing new lots of media, reagents, and test panels with reference strains before routine use. The verification process should be documented and reviewed by the QC supervisor or laboratory director.

Culture Media Quality Control

Sterility Testing

Each batch of prepared culture media must be checked for sterility before use. A representative sample from each batch is incubated under the conditions that support growth of common contaminants. For agar plates, a percentage of each batch is incubated at the appropriate temperature for a defined period and examined for colony growth. For broth media, a sample is incubated and observed for turbidity.

Sterility testing detects contamination introduced during media preparation, including improper sterilization, contaminated ingredients, or poor aseptic technique during pouring. A contaminated batch must be discarded and the preparation process reviewed.

Growth Promotion Testing

Growth promotion testing confirms that a medium supports the growth of the organisms it is intended to cultivate. Reference strains with known growth characteristics are inoculated onto or into the medium and incubated under standard conditions. The medium passes if the expected growth is observed within the expected time frame.

Growth promotion testing is particularly important for selective media, where the balance between supporting target organisms and inhibiting non-target organisms can be disrupted by preparation errors, expired ingredients, or improper storage. A selective medium that fails to support target growth or fails to inhibit non-target growth must be investigated and the batch rejected.

Selective and Differential Performance

Selective media are designed to inhibit certain organisms while allowing others to grow. Differential media are designed to distinguish organisms based on biochemical reactions visible as colony color, hemolysis, or other phenotypic characteristics. Both functions must be verified with appropriate control strains.

For example, a selective medium for gram-negative pathogens should be tested with a target organism expected to grow and a non-target organism expected to be inhibited. A differential medium should be tested with organisms expected to produce positive and negative reactions. The QC record should document the strains used, the expected results, and the observed results.

Documentation Requirements

Each media batch should be assigned a unique identifier that links the preparation date, ingredients, lot numbers, sterilization cycle, and QC test results. The media preparation log should include the medium name, preparation date, technician initials, sterilization parameters, pH if applicable, and QC results. This documentation supports traceability when a problem is identified after the media has been in use.

Organism Verification and Reference Strains

Role of Reference Strains

Reference strains with known characteristics are the foundation of organism verification. These strains are used to test biochemical panels, identification systems, and antimicrobial susceptibility testing methods. The Clinical and Laboratory Standards Institute (CLSI) publishes quality control ranges for reference strains used in antimicrobial susceptibility testing [20]. Reference ranges for quality control strains are published in the CLSI M100 document [20].

For antimicrobial susceptibility testing, the choice of quality control strains depends on the antimicrobial agents and testing method. For example, CLSI-approved quality control strains such as Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 29213 have been used to validate broth microdilution testing for fastidious organisms when no species-specific quality control strains are approved [21]. Minimal inhibitory concentrations determined with these surrogate strains were mostly within the CLSI-approved quality control ranges for defined antimicrobial agents [21].

Verification of Commercial Identification Systems

Commercial identification systems require verification with reference strains before routine use and with each new lot of test panels or reagents. The verification process should include organisms that test the full range of biochemical reactions the system is designed to detect.

The laboratory should maintain a collection of reference strains that represent the organisms most commonly encountered in its patient population. This collection should be stored under conditions that preserve viability and phenotypic stability. Stock cultures should be checked periodically for purity and identity.

Frequency of Testing

The frequency of organism verification testing depends on the test system, the manufacturer recommendations, and accreditation requirements. New lots of media, reagents, and test panels should be tested before routine use. Ongoing quality control testing may be required daily, weekly, or per batch, depending on the system.

Some laboratories use an individualized quality control plan that adjusts testing frequency based on historical performance [28]. An individualized quality control plan allows the laboratory to reduce testing frequency for systems with consistent performance while increasing testing for systems with a history of problems. The plan must be based on documented performance data and approved by the laboratory director.

Equipment Monitoring and Calibration

Temperature-Dependent Equipment

Incubators, refrigerators, freezers, and water baths must be monitored to ensure they maintain the temperatures required for culture growth and reagent storage. Temperature should be recorded at least once daily, and continuous monitoring with alarms is recommended for critical equipment.

Temperature monitoring devices should be calibrated periodically against a certified reference thermometer. The calibration schedule should be documented, and calibration records should be retained. A temperature reading outside the acceptable range requires investigation and corrective action, including assessment of any specimens or cultures that may have been affected.

Autoclave and Sterilization Monitoring

Autoclaves used for media preparation and waste decontamination must be monitored to ensure effective sterilization. Physical indicators such as temperature and pressure recordings should be reviewed for each cycle. Chemical indicators should be used with each load. Biological indicators, such as spore strips, should be used periodically to confirm sterilization effectiveness.

A failed biological indicator requires immediate investigation. The autoclave should be taken out of service until the cause is identified and corrected. Any items processed since the last successful biological indicator test should be considered potentially non-sterile.

Pipettes and Other Measuring Devices

Pipettes used for preparing reagents, inoculating media, and performing quantitative assays must be calibrated periodically. Calibration verifies that the pipette delivers the intended volume within acceptable tolerance. Pipettes should be calibrated at regular intervals and after any event that could affect accuracy, such as a drop or repair.

Calibration records should include the pipette identification number, calibration date, results, and the next scheduled calibration date. Pipettes that fail calibration should be removed from service and repaired or replaced.

Centrifuges and Other Equipment

Centrifuges used for specimen processing should have their speed and temperature verified periodically. Safety features such as lid locks and imbalance sensors should be tested. Other equipment, including biological safety cabinets, should be certified at regular intervals to ensure proper operation.

Biological safety cabinets require certification after installation, after relocation, and at regular intervals thereafter. Certification verifies airflow, HEPA filter integrity, and containment performance. The certification record should be retained and reviewed.

Assay Validation and Verification

Validation Before Routine Use

Evaluation of all assays before their inclusion in the daily routine work of the laboratory is of utmost importance [6]. A new assay or a modified version of an existing assay must be validated before patient testing. Validation demonstrates that the assay performs as intended in the local laboratory setting.

The validation process should include assessment of accuracy, precision, analytical sensitivity, and analytical specificity. For quantitative assays, the linear range and limits of detection should be established. For qualitative assays, the threshold for positive results should be confirmed.

Verification of Commercial Assays

Commercial assays that have been validated by the manufacturer require verification instead of full validation. Verification confirms that the assay performs as claimed in the local laboratory. The verification process should include testing of known positive and negative specimens, assessment of precision, and confirmation of the limit of detection if applicable.

A cross-matrix performance framework for cytomegalovirus molecular testing demonstrated robust performance across clinically relevant specimen types, including oral swabs, saliva, dried urine spots, dried blood spots, umbilical cord blood, amniotic fluid, placental tissue, vaginal swabs, and breast milk [14]. Linearity of detection in fluid samples ranged from 0.96 to 1.00, and limits of detection in fluid samples ranged from 2.22 to 2.83 log IU/ml [14]. This example illustrates the type of performance data that should be generated during assay verification.

Documentation of Validation and Verification

The validation or verification process should be documented in a protocol that describes the specimens tested, the methods used, the acceptance criteria, and the results. The final report should include a conclusion about whether the assay is suitable for routine use and any limitations identified during the process.

The validation report should be reviewed and approved by the laboratory director or designee. The report should be retained as part of the laboratory quality management system.

Quality Control for Molecular Microbiology Assays

Application of QC Tools

Application of quality control tools in molecular microbiology assays is crucial to ensure the accuracy of results and appropriate patient management [6]. Molecular assays have unique QC requirements related to nucleic acid extraction, amplification, and detection.

Internal quality control for molecular assays includes the use of positive and negative controls in each run. Positive controls confirm that the assay can detect the target if present. Negative controls confirm that contamination has not occurred. Extraction controls confirm that nucleic acid was successfully extracted from the specimen.

External Quality Control for Molecular Assays

External quality control programs for molecular microbiology include specific programs for quantitative determination of viral load of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV), two highly important molecular markers in clinical settings due to their prognostic value and utility as a treatment guide [6]. Participation in these programs allows the laboratory to compare its results with other laboratories and detect systematic errors.

Contamination Control

Contamination is a major risk in molecular microbiology assays because of the amplification step. Amplicon contamination can produce false-positive results. QC practices to prevent contamination include physical separation of pre-amplification and post-amplification areas, use of dedicated pipettes and reagents, and inclusion of negative controls in each run.

A contamination event requires immediate investigation. The source of contamination should be identified and eliminated. All results from the affected run should be considered unreliable and repeated.

Quality Control for Specialized Diagnostic Methods

Fluorescence In Situ Hybridization

Fluorescence in situ hybridization (FISH) in a routine diagnostic setting in microbiology requires strict quality control measures to ensure consistent high-quality and reliable assay results [7]. Diagnostic FISH assays on tissue sections are used for detection of biofilm-associated infections including infective endocarditis, oral biofilms, and device-associated infections, as well as infections due to fastidious or uncultured microorganisms such as Treponema species, Tropheryma whipplei, Bartonella, Coxiella burnetii, or Brachyspira [7].

Quality control requirements for microbiological diagnostic FISH applications include validation of probe specificity and sensitivity, optimization of hybridization conditions, and inclusion of appropriate positive and negative control tissues in each run [7]. The interpretation of FISH results should be performed by trained personnel with documented competency.

Antimicrobial Susceptibility Testing

Antimicrobial susceptibility testing requires rigorous quality control to ensure that results are reliable for clinical decision-making. Quality control strains with known minimal inhibitory concentration ranges are tested alongside patient isolates. The results for quality control strains must fall within the acceptable range for the test to be valid.

For levonadifloxacin, a novel antibiotic based on the benzoquinolizine subclass of fluoroquinolone, reference MIC and disk diffusion methods were approved by CLSI, and reference ranges for quality control strains were published in the CLSI M100 document [20]. The breakpoints were derived in concordance with US FDA, European Committee on Antibiotic Susceptibility Testing (EUCAST), and CLSI approaches [20].

For fastidious organisms without approved quality control strains, surrogate quality control strains may be used. For example, E. faecalis ATCC 29212 and S. aureus ATCC 29213 were proposed as surrogate quality control strains for validation of antimicrobial susceptibility testing results for Mycoplasma hyorhinis by broth microdilution [21].

Statistical Quality Control and Risk Management

Risk-Based QC Design

Quality control in the laboratory aims to reduce the risk of harm to a patient due to erroneous results, as highlighted by CLSI guidance for statistical quality control [24]. Risk-based QC design uses patient risk parameters to determine the appropriate QC strategy for each test.

A spreadsheet tool based on Parvin's patient risk model calculates the expected number of unreliable final patient results and the maximum expected number of unreliable final patient results based on the current QC strategy [24]. After the quality requirements, performance parameters, practical run size, QC rules, and number of QC results are input, the laboratory can quickly obtain the maximum expected number of unreliable final patient results, maximum run size, and other data [24]. The QC strategy conforming to the risk requirements can be developed by changing the QC rules or the quantity of run size [24].

QC Rules and Interpretation

QC rules define the criteria for accepting or rejecting a run based on control results. Common QC rules include 1-2s, 1-3s, 2-2s, R-4s, and 4-1s, where the first number indicates the number of control observations and the second number indicates the standard deviation limit. A run is rejected when control results violate the defined rules.

The choice of QC rules depends on the test method, the quality requirements, and the risk tolerance. More stringent QC rules reduce the risk of releasing erroneous results but increase the frequency of run rejection and repeat testing.

Individualized Quality Control Plans

An individualized quality control plan allows the laboratory to adjust QC frequency and rules based on documented performance [28]. The plan is based on the laboratory's historical QC data, the test method's stability, and the risk of patient harm from erroneous results.

The individualized quality control plan must be documented and approved. It should include criteria for reverting to standard QC if performance deteriorates. The plan should be reviewed periodically and updated as needed.

Records and Documentation

Required Records

The laboratory quality management system requires documentation of all QC activities. Required records include media preparation logs, QC test results, equipment monitoring records, calibration certificates, validation and verification reports, and corrective action reports.

Each record should include sufficient information to identify the test, the date, the technician, the materials used, and the results. Records should be legible, permanent, and retrievable. Electronic records should be backed up and protected from unauthorized alteration.

Corrective Action Documentation

When a QC failure occurs, the laboratory must document the investigation and corrective action. The corrective action report should describe the problem, the cause, the action taken, and the verification that the action was effective. The report should also assess the impact on patient results.

Corrective action reports should be reviewed by the QC supervisor or laboratory director. Trends in QC failures should be analyzed to identify recurring problems and implement preventive actions.

Audit and Review

Internal audits assess whether the laboratory's QC practices conform to its policies and procedures. Audits should be conducted at regular intervals and cover all aspects of the testing process. Audit findings should be documented and corrective actions tracked to completion.

External audits, such as those conducted by accreditation bodies, provide an independent assessment of the laboratory's quality management system. The laboratory should be prepared for external audits by maintaining complete and current documentation.

Common Failure Patterns and Troubleshooting

Media-Related Failures

Media-related QC failures include contamination, failure to support target growth, and failure to inhibit non-target growth. Common causes include improper sterilization, contaminated ingredients, incorrect preparation, expired media, and improper storage.

When a media QC failure occurs, the affected batch should be quarantined and investigated. The investigation should review the preparation process, the ingredients, and the storage conditions. If the cause cannot be identified, the batch should be discarded.

Equipment-Related Failures

Equipment-related QC failures include temperature excursions, calibration failures, and sterilization failures. Common causes include equipment malfunction, power outages, and improper use.

When an equipment failure occurs, the equipment should be taken out of service and the affected specimens or cultures assessed. The equipment should be repaired or replaced and requalified before returning to service.

Contamination Events

Contamination events in molecular assays can produce false-positive results. Common causes include amplicon contamination, contaminated reagents, and improper technique.

When a contamination event occurs, the affected run should be repeated. The source of contamination should be identified and eliminated. Additional measures, such as increased frequency of decontamination or changes to workflow, may be needed.

Identification and Susceptibility Testing Failures

Identification and susceptibility testing failures occur when reference strain results fall outside acceptable ranges. Common causes include degraded reagents, improper storage, and errors in test performance.

When a reference strain result falls outside the acceptable range, the test should be repeated. If the failure persists, the reagent lot should be investigated and the test system evaluated.

Safety and Regulatory Context

Biosafety Considerations

Microbiology laboratories handle potentially hazardous microorganisms. The World Health Organization Laboratory Biosafety Manual provides guidance on safe handling of biological materials [2]. Laboratory biosafety practices are an integral part of quality control because they protect personnel and prevent contamination of specimens and cultures.

Biosafety practices include use of biological safety cabinets for procedures that generate aerosols, proper personal protective equipment, and safe handling and disposal of sharps. Laboratory personnel should receive biosafety training and demonstrate competency before working with hazardous materials.

Regulatory Requirements

Clinical microbiology laboratories are subject to regulatory requirements that include quality control provisions. The U.S. Food and Drug Administration has classified assayed quality control material for clinical microbiology assays as a medical device, establishing regulatory requirements for these products [26]. Laboratories should be aware of the regulatory status of the QC materials they use.

The International Organization for Standardization standard ISO 15189 specifies requirements for quality and competence in medical laboratories [23]. Laboratories seeking accreditation to ISO 15189 must comply with its requirements, including those for quality control. The International Federation of Clinical Chemistry and Laboratory Medicine has published recommendations on internal quality control that are derived from ISO 15189, although there are some divergences between the recommendations and the standard [23]. Laboratories and accreditation bodies may not deviate from the requirements of ISO 15189 [23].

Professional Escalation Criteria

QC personnel should escalate issues to the laboratory director or designee when a QC failure cannot be resolved, when patient results may have been affected, or when a pattern of failures suggests a systemic problem. Escalation should occur promptly and include documentation of the issue and the actions taken.

The laboratory director is responsible for ensuring that QC practices meet regulatory and accreditation requirements and that patient results are reliable. The director should be informed of significant QC failures and involved in decisions about corrective actions and result reporting.

Responsibilities of QC Personnel

QC Technician

The QC technician performs the daily QC tests, records results, and maintains QC documentation. Responsibilities include preparing media and reagents, testing new lots, monitoring equipment, and documenting corrective actions.

The QC technician should have training in microbiology techniques and QC procedures. The technician should understand the principles behind each QC test and be able to recognize when results are unacceptable.

QC Supervisor

The QC supervisor oversees the QC program, reviews QC results, and investigates failures. Responsibilities include developing QC procedures, training staff, analyzing QC trends, and ensuring that corrective actions are implemented.

The QC supervisor should have advanced training in microbiology and quality management. The supervisor should be able to interpret QC data and make decisions about test system acceptability.

Laboratory Director

The laboratory director has ultimate responsibility for the quality of laboratory results. Responsibilities include approving QC policies and procedures, reviewing QC reports, and ensuring that the laboratory meets regulatory and accreditation requirements.

The laboratory director should be a qualified professional with expertise in microbiology and laboratory management. The director should be accessible to QC personnel for consultation on complex issues.

Practical Implementation Steps

Step 1: Assess Current QC Practices

Review existing QC procedures, records, and performance. Identify gaps in coverage, documentation, or compliance. This assessment provides the baseline for improvement.

Step 2: Develop or Update QC Policies and Procedures

Write or revise QC policies and procedures that address all aspects of the testing process. Include specific procedures for media testing, organism verification, equipment monitoring, and assay validation. Define acceptance criteria and corrective action requirements.

Step 3: Train Personnel

Train all laboratory personnel on QC policies and procedures. Document training and verify competency. Provide refresher training at regular intervals and after procedure changes.

Step 4: Implement the QC Program

Begin using the new or revised QC procedures. Ensure that all required records are maintained. Monitor QC results and address failures promptly.

Step 5: Audit and Improve

Conduct internal audits to assess compliance with QC policies and procedures. Analyze QC data for trends. Implement corrective and preventive actions as needed. Review the QC program periodically and update as needed.

Frequently Asked Questions

What is the difference between quality control and quality assurance in microbiology?

Quality assurance refers to the quality control activities related to analytical procedures performed in the clinical microbiology laboratory, and it should include both external and internal quality assessment [6]. Quality control is the operational component that includes testing control samples, monitoring equipment, and documenting results. Quality assurance is the broader system that encompasses quality control plus the policies, procedures, and management activities that ensure reliable results.

How often should culture media be tested for quality control?

Each new batch of prepared culture media should be tested before use. Testing should include sterility checks and growth promotion testing with appropriate reference strains. The frequency of ongoing testing depends on the medium type, the manufacturer recommendations, and accreditation requirements. Some laboratories use individualized quality control plans that adjust testing frequency based on historical performance [28].

What are the responsibilities of a microbiology quality control technician?

A microbiology quality control technician performs daily QC tests, records results, and maintains QC documentation. Responsibilities include preparing and testing media, verifying organism identification systems, monitoring equipment, and documenting corrective actions. The technician must recognize unacceptable results and escalate issues according to laboratory policy.

What quality control strains are used for antimicrobial susceptibility testing?

Quality control strains with known minimal inhibitory concentration ranges are used for antimicrobial susceptibility testing. CLSI publishes reference ranges for quality control strains in the CLSI M100 document [20]. For organisms without approved quality control strains, surrogate strains may be used. For example, E. faecalis ATCC 29212 and S. aureus ATCC 29213 were proposed as surrogate quality control strains for Mycoplasma hyorhinis testing [21].

How does external quality assessment differ from internal quality control?

Internal quality control detects random and systematic errors through inclusion of quality control samples in assays, equipment monitoring, and audit [6]. External quality assessment is used for laboratory intercomparisons, detection of random and systematic errors, evaluation of reagent or commercial kit suitability, and continuing education [6]. External quality assessment involves testing specimens provided by an external program and comparing results with other laboratories.

What should be done when a quality control result falls outside the acceptable range?

When a QC result falls outside the acceptable range, the test should be repeated. If the failure persists, the reagent lot, equipment, and procedure should be investigated. The affected patient results should be assessed for reliability. The investigation and corrective action should be documented. If the issue cannot be resolved, it should be escalated to the laboratory director.

Why is assay validation important before routine use?

Evaluation of all assays before their inclusion in the daily routine work of the laboratory is of utmost importance [6]. Validation demonstrates that the assay performs as intended in the local laboratory setting, including accuracy, precision, and limits of detection. Without validation, the laboratory cannot know whether the assay produces reliable results for patient specimens.

What is an individualized quality control plan?

An individualized quality control plan allows the laboratory to adjust QC frequency and rules based on documented performance [28]. The plan is based on historical QC data, test method stability, and the risk of patient harm from erroneous results. The plan must be documented, approved, and reviewed periodically.

Related Diagnostic Guides

• Quality Control in the Microbiology Laboratory: Key Practices for Reliable Results
• How to Calibrate a Refractometer for Culture Media and Solution Checks
• How to Store and Handle Agar Plates and Culture Media for Microbiology
• Aseptic Technique in Microbiology Lab: Essential Steps and Best Practices
• Quality Control Strains for Antimicrobial Susceptibility Testing: Selection and Maintenance

References and Further Reading

• Laboratory Quality Management System Handbook. World Health Organization.
• Laboratory Biosafety Manual. World Health Organization.
• Assay Guidance Manual. National Center for Advancing Translational Sciences.
• Bioanalytical Method Validation Guidance. U.S. Food and Drug Administration.
• NCBI Literature Resources. National Center for Biotechnology Information.
• [Quality control in molecular microbiology].. Enfermedades infecciosas y microbiologia clinica, 2008.
• Quality Control in Diagnostic Fluorescence In Situ Hybridization (FISH) in Microbiology.. Methods in molecular biology (Clifton, N.J.), 2021.
• Quality control in microbiology: a review and bibliography.. Clinics in laboratory medicine, 1986.
• [Quality control in microbiology].. Quaderni Sclavo di diagnostica clinica e di laboratorio, 1982.
• Strategies for quality management in clinical microbiology.. Clinics in laboratory medicine, 1995.
• Quality control in microbiology. II. The need for standards.. American journal of clinical pathology, 1974.
• Clinical microbiology quality assurance program: a Taiwan experience.. Zhonghua Minguo wei sheng wu ji mian yi xue za zhi = Chinese journal of microbiology and immunology, 1995.
• Quality control of the isolation rate of pathogens in medical microbiology laboratories.. The Journal of hygiene, 1976.
• Evaluation of a semi-automated method for detection of cytomegalovirus DNA in multiple sample types.. 2026.
• Fine-tuned large language models enhance influenza forecasting.. 2026.
• A Classic Fold With a Twist: Structural Architecture of Dhillonvirus Phage Bas18.. 2026.
• HPV Prevalence Among Inuit Women in Northern Quebec, Canada: A Pre- and Post-Vaccination Analysis.. 2026.
• Shaping postoperative outcomes: microbiota-modifying dietary fiber interventions in colorectal cancer treatment.. 2026.
• Healthcare-associated infections and antimicrobial resistance in Canadian acute care hospitals, 2020-2024.. 2026.
• India-discovered levonadifloxacin & alalevonadifloxacin: A review on susceptibility testing methods, CLSI quality control and breakpoints along with a brief account of their emerging therapeutic profile as a novel standard-of-care.. Indian Journal of Medical Microbiology, 2022.
• Provisional Use of CLSI-Approved Quality Control Strains for Antimicrobial Susceptibility Testing of Mycoplasma (‘Mesomycoplasma’) hyorhinis. Microorganisms, 2021.
• Cefiderocol MIC quality control ranges in iron-depleted cation-adjusted Mueller-Hinton broth using a CLSI M23-A4 multi-laboratory study design.. Diagnostic microbiology and infectious disease, 2017.
• Divergences between IFCC recommendations for internal quality control and ISO standards.. Clinica chimica acta, international journal of clinical chemistry, 2025.
• A spreadsheet tool for designing statistical quality control programs based on patient risk parameters.. Clinical Biochemistry, 2023.
• Quality control in microbiology (author's transl). Annali Sclavo Rivista Di Microbiologia E Di Immunologia, 1977.
• Medical Devices, Immunology and Microbiology Devices, Classification of the Assayed Quality Control Material for Clinical Microbiology Assays. Final order. Federal Register, 2017.
• Quality control analytical methods: strategies to ensure a robust quality-control microbiology program.. International Journal of Pharmaceutical Compounding, 2013.
• The Individualized Quality Control Plan-Coming Soon to Clinical Microbiology Laboratories Everywhere!. Clinical Microbiology Newsletter, 2015.

This article is educational and does not replace validated laboratory procedures, institutional biosafety review, manufacturer instructions, or professional interpretation.