Standards, QA/QC and Constancy Testing of Medical Devices

Standard ISO definition

Documented agreements with technical specifications or criteria used as rules, guidelines, or definitions to ensure materials, products, processes, and services are fit for their purpose

Standard general definition

Represent minimum acceptable criteria, not 'state of the art,' established by stakeholder consensus at a specific time

Standard Examples (3)

• Safety and essential performance of a medical device

• Calculation of minimum detectable value in analytical instruments

• Acceptance and constancy tests

Safety and Essential Performance of a Medical Device

Ensures that medical devices function reliably and do not pose unnecessary risks to patients or operators during normal use

Calculation of Minimum Detectable Value in Analytical Instruments (2)

• Specifies the smallest quantity of a substance that an analytical instrument can accurately detect

• Ensures sensitivity and reliability in measurements

Acceptance and constancy tests

Procedures to confirm that instruments meet specified performance standards at installation (acceptance) and maintain consistent performance over time (constancy)

International Organisations Setting Standards (4)

establish standards in specific domains

• International Electrotechnical Commission (IEC)

• International Organisation for Standardisation (ISO)

• Joint Technical Committee (JTC 1)

International Electrotechnical Commission (IEC) (2)

• Sets standards for electrical and electronic devices

• Fx.: X-ray generators, spectrophotometers, electronic balances

International Organisation for Standardisation (ISO) (2)

• Sets standards across all fields except electrical and electronic standards

• Fx.: Quality management processes, X-ray films

Joint Technical Committee (JTC 1)

Collaborates between ISO & IEC to set standards for ICT hardware and software

European Norms (EN)

European standards set by European standard organizations under the European Commission's directive

European Standard Hierarchy (2)

• ENs are typically equal to or higher than International Standards

• Individual European states may set standards surpassing European Norms

European Standard Setting Organizations (3)

• European Committee for Electrotechnical Standardization (CENELEC)

• European Committee for Standardization (CEN)

• European Telecommunications Standards Institute (ETSI)

Quality Assurance (QA) Legal Definition

All those planned and systematic actions necessary to provide adequate confidence that a structure, system, component, or procedure will perform satisfactorily complying with agreed standards - (EU Directive 2013/59/EURATOM)

Quality Assurance (QA) Legal def. meaning

This means planning and organizing everything in advance to ensure a device, system, or process works properly and meets agreed standards. It’s about making sure no problems happen in the first place

Quality Assurance (QA) Nature

Prospective, managerial-level process

Quality Assurance (QA) Purpose

Focuses on preventing defects in medical devices or clinical services before they occur

Quality Control (QC) Legal Definition

The set of operations (programming, coordinating, implementing) intended to maintain or to improve quality. It covers monitoring, evaluation, and maintenance at required levels of all characteristics of performance of equipment that can be defined, measured, and controlled - (Directive 2013/59/EURATOM)

Quality Control (QC) Legal Definition Meaning

This involves checking and testing devices, systems, or processes after they are in use to ensure they meet the required performance levels. If something isn’t working as expected, it focuses on fixing or improving it.

Quality Control (QC) Nature

Retrospective, operational process

Quality Control (QC) Purpose

Involves monitoring and evaluating the performance of medical devices or clinical services to detect and correct defects

Difference b/n QA and QC (2)

• QA is preventive and focuses on planning and managing processes to avoid problems before they happen. It ensures that everything is done the right way from the start

• QC is reactive and focuses on inspecting and testing the final product or service to identify and fix any issues

Why is Regular Constancy Testing Necessary for Medical Devices? (2)

• Degradation of Performance Indicators

• Degradation in Safety Features

Degradation of Performance Indicators (2)

• Regular testing ensures accuracy, signal-to-noise ratio (SNR), and measurement resolution remain within acceptable limits

• Degradation in these parameters can lead to misdiagnosis or ineffective therapy, potentially worsening patient health outcomes

Degradation in Safety Features (2)

• Testing helps identify and rectify any deterioration in safety mechanisms

• This reduces the risk of harm to patients and healthcare professionals operating the devices

Components of a Medical Device QA-QC Programme (6)

• Device Procurement

• Acceptance Testing

• Commissioning

• Constancy Testing

• Preventive Maintenance

• Ongoing Quality Improvement

Device Procurement (2)

• Purpose:

  • Identify clinical needs and establish device specifications to meet these requirements

• Responsibility:

  • Multi-professional departmental QA team

Acceptance Testing

Perform safety checks and verify if the device specifications align with those outlined in the procurement document

Commissioning (3)

• Prepare the device for clinical use

• Includes determining user settings and setting baseline and action values for future performance testing

  • Fx.: warning or maximum allowable limits

Constancy Testing (2)

= stability testing

• Monitors performance indicators such as SNR and accuracy to ensure consistent operation

Preventive Maintenance

Regular servicing to prevent breakdowns and maintain performance reliability

Ongoing Quality Improvement (2)

• Regular software and device upgrades

• Decommissioning outdated devices and replacing them with newer, advanced models

Constancy Testing Charts (photo)

Purpose of Constancy Testing Chart

Ensure the equipment's performance remains consistent over time

Baseline value of Constancy Testing Chart

= Average value

Warning Limit of Constancy Testing Chart (4)

• Predefined threshold signaling approaching unsafe condition

• Allows time for corrective actions

  • can be used on patients cautiously

• Set lower than the maximum allowable limit

Maximum Allowable Limit of Constancy Testing Chart (3)

• Absolute upper limit for safe operation

• Exceeding leads to safety risks or malfunction

• Illegal to use on patients!

Safety and Device Performance Terminology (2)

• EU Medical Device Regulation

• IEC (IEC 60601-1) Terminology

EU Medical Device Regulation - General Safety

Refers to risks to patients and users from various physical, chemical, or other agents associated with a medical device

EU Medical Device Regulation - Clinical Effectiveness of the device (2)

• Describes the ability of a device to achieve its intended purpose as claimed by the manufacturer

• Leads to clinical benefit for patients when used as intended

IEC (IEC 60601-1) Terminology - General Safety

Ensures freedom from unacceptable risk directly caused by physical hazards when medical equipment is used under both normal and single fault conditions

IEC (IEC 60601-1) Terminology - Clinical Performance

Refers to the performance of a clinical function other than basic safety, where a loss or degradation beyond specified limits results in an unacceptable risk