Quality Assurance in Diagnostics

Learning Objectives

• Students will be able to define quality assurance.
• Students will be able to list important terms in quality assurance.
• Students will be able to discuss the basic principles of quality assurance.
• Students will be able to describe different components of quality assurance.
• Students will be able to describe the importance and necessity of quality assurance.
• Students will be able to classify types of diagnostic tests based on the type of result obtained and method of analysis.
• Students will be able to describe accuracy and precision.
• Students will be able to describe indicator values of diagnostic tests including sensitivity, specificity, test efficiency, predictive values.
• Students will be able to calculate diagnostic values such as sensitivity, specificity, overall test efficiency, and predictive values.
• Students will be able to use diagnostic values to determine the acceptability of test methods.

Chapter Outline

• Definition of important terms in quality assurance.
• Essential components of quality systems.
• Aspects of quality assurance.
• Characteristics of quality assurance.
• Basic components of quality assurance programs.
• Benefits of quality assurance.
• The purpose of a health laboratory.
• Errors in clinical laboratories: clerical errors, sampling errors, analytical errors.
• Types of diagnostic tests.
• Accuracy and precision.
• Indicators of values of diagnostic tests (sensitivity, specificity, test efficiency, predictive values).

What is Quality Assurance?

• Quality Assurance (QA) is the development and implementation of measures to ensure reliable laboratory service.

What is Quality?

• Quality is the ability of a product or service to satisfy stated or implied needs of a specific customer.
• It's achieved by conforming to established requirements and standards.

Quality Assurance vs. Quality Control

• Quality Assurance (QA) is a proactive system designed to prevent errors for consistent high-quality results in testing processes.
• Quality Control (QC) is a reactive method of monitoring and testing to identify and address deviations from quality standards. QA focuses on prevention while QC focuses on correcting.

Definitions of Terms

• Pre-analytic: activities related to specimen collection, transport, and handling (before testing)
• Analytical: testing phase
• Post-analytic: handling of results, reporting, and follow-up (after testing).
• Clerical Errors: mistakes made in writing and recording test results.
• Sampling errors: mistakes in collecting, handling or transporting specimen.
• Accuracy: Closeness of a measured result to the true value.
• Precision: Closeness of replicated measurements to each other.

Definition of a Lab Quality System

• The organizational structure, responsibilities, processes, procedures, and resources for implementing quality management in a laboratory.

Why is the Quality System Important to Patient Sample Testing?

• Quality systems ensure quality is fundamental to all activities.
• It sets standards for quality, meets/exceeds customer expectations, and provides means to correct problems.
• It also ensures monitoring, evaluation, and improvement systems.
• A system for quality reduces costs.

Essential Components of a Quality System

• Organization: management organizational structure.
• Personnel: human resource planning, hiring, training, supervision, performance management, retention
• Equipment: selection, acquisition, initial calibration, maintenance, service and repair, troubleshooting, disposition.
• Purchasing & Inventory: procurement, receiving, storage, inventory management, record keeping.
• Processes & Control: standard operating procedures, specimen management, quality control.
• Documents & Records: standardized forms, document approval, document distribution, document storage/retrieval, document destruction.
• Information Management: Information flow, Data collection and management, Patient privacy and confidentiality, Computer skills.
• Occurrence Management: written procedures for addressing errors, corrective actions, occurrence records, occurrence reporting.
• Assessment: External quality assessment, Internal audit or self-evaluation, Improvement measures.
• Process Improvement: on-going data collection, improvement measures.
• Service & Satisfaction: monitoring customer satisfaction, process improvement, rewards.
• Facilities & Safety: testing and storage areas, safety procedures and records.

Quality System Organization

• Quality Policy & Standards, Sufficient Resources, Clearly Defined Roles & Accountability, Culture Committed to Quality

Quality System Personnel

• Human Resource Planning, Hiring, Retentions, Training, Supervision, Performance Management

Quality System Equipment

• Selection, Acquisition, Installation & Initial Calibration, Maintenance, Service & Repair, Troubleshooting, Disposition

Quality System Purchasing and Inventory

• Procurement, Receiving, Storage, Inventory Management, Record Keeping

Quality System Process Control

• Standard Operating Procedures, Specimen Management, Quality Control

Quality System Documents and Records

• Standardized Forms, Document Approval, Document Distribution, Document Storage/Retrieval, Document Destruction

Quality System: Information Management

• Information Flow, Data Collection and Management, Patient Privacy & Confidentiality, Computer Skills

Quality System: Occurrence Management

• Written Procedures for Addressing Errors, Corrective Actions, Occurrence Records, Occurrence Reporting

Quality System Essential Assessment

• External Quality Assessment, Improvement Measures, Internal Audit or Self-Evaluation

Quality System Process Improvement

• On-Going Data Collection, Improvement Measures

Quality System: Service and Satisfaction

• Monitoring Customer Satisfaction, Process Improvement, Rewards

Quality System Facilities and Safety

• Testing and storage areas, safety procedures, safety records

Total Quality Management

• TQM addresses all areas of laboratory practice.
• It includes lab services & resources.

Purpose of Health Laboratory

• Provide patient laboratory results.
• Aid in diagnosis of disease
• Help in determining prognosis.
• Monitor the effects of treatment.
• Monitor disease outbreaks.

Characteristics and Aspects of Quality Assurance

• Three phases affect useful patient results (pre-analytic, analytic, post-analytic).
• Aspects of each phase are important for effective quality assurance.

The Quality Assurance Cycle (diagram)

• Pre-testing: Patient/client prep, sample collection, sample receipt, accessioning, & sample transport.
• Testing phase: Testing, Quality control
• Post-testing: Reporting, record keeping, Data and lab management, Safety.

Basic Components of QA

• Internal quality assessment (IQA).
• External quality assessment (EQA).
• Standardisation of processes.
• Management and organisation.
• Includes QC, EQA and quality improvement.

CON... (Internal and External QA)

• Internal QA involves implementing well-designed specimen-collection procedures.
• External QA includes objective checks on lab results.

Benefits of Quality Assurance

• Help physicians, patients and clients.
• Creates a good reputation.
• Motivates staff.
• Is cost-effective.
• Prevents complaints.
• Builds trust.

Three Stages of Analysis

• Pre-analytic
• Analytic
• Post-analytic
• Errors in any stage can affect the system

Pre-Analytic Errors

• Test Ordering
• Specimen Collection
• Specimen Handling

Pre-Analytic Specimen Collection Errors

• Wrong Patient ID, Anticoagulant, Volume, Process, Hemolysis, IV contamination, Prolonged tourniquet

Preventing and Detecting Errors - Before Testing

• Check storage and room temperature
• Select an appropriate testing workspace
• Check inventory and expiration dates
• Review testing procedures
• Collect appropriate specimens

Analytic Errors

• Instrumental problems
• Operator error
• Reagent Issues
• Methodological errors
• Environmental factors

Quality Assurance vs. Quality Control (table format)

• Definition for both and comparison of Examples

Quality Control Material

• Assessing the analytic phase.
• Acceptance versus rejection of patient results.
• Includes 2 or 3 control materials.

Westgard Rules

• A set of statistical quality control guidelines for laboratories.
• Used to monitor accuracy and precision of tests.

Rules (1-3s, 2-2s, R-4s) (details)

• Detailed explanation for each rules.

Example calculation of Standard Deviation (SD)

• Calculations used in example to explain SD.

The standard deviation (SD)

• Measure of variability or spread of data from the mean.
• A lower SD indicates higher precision; higher SD indicates more variability/low precision.

Precision Calculations (%CV)

• Precision calculations using SD and %CV.

Examples related to precision calculations

Accuracy Calculations

• Accuracy calculation methods using bias data.
• Calculating % accuracy error

Indicators of Diagnostic Tests

• Clinicians depend on lab for accurate results.
• Aid in diagnosis, patient prognosis, and treatment effectiveness assessment; determine relative risk of disease.

Indicators of Diagnostic Tests and Medical Usefulness

• Tests have inherent errors.
• No test can detect all cases of disease or all cases without disease.
• There may not be a test with 100% specificity and sensitivity.

Four Possible Outcomes to Test Results and Disease Diagnosis

• True Positive (TP)
• True Negative (TN)
• False Positive (FP)
• False Negative (FN)

Results of Disease Screening Testing: Possible Outcomes (table)

• Table showing results of various screening testing

Positive and Negative Predictive Values (PPV & NPV)

• Explanation on how these values are calculated.
• Higher values suggest better reliability in diagnosing patients

Example: Screening Test (details)

True Positives, False Positives, True Negatives, False Negatives

• Explanation on these terms with an example

Indicators of Diagnostic values of Test: Definitions

• Sensitivity (calculated using True Positives and False Negatives)
• Specificity (calculated using True Negatives and False Positives)

Sensitivity/Specificity definitions based on diagnosis outcomes.