How to use this case study
This example follows a sterile catheter from raw material to point of use. Challenge whether design, processing and packaging evidence support the same released product after manufacture, sterilisation, transport and ageing.
Case at a glance
A sterile, single-use peripheral catheter is inserted by trained healthcare professionals for short-term vascular access. It consists of a polymer catheter tube, metal needle, hub, protective components and sterile-barrier package. It is supplied sterilised and is not intended for reuse.
Clinical value
Reliable vascular access with controlled insertion and fluid connection.
Product boundary
Finished device, materials, manufacturing residues, sterilisation and packaging system.
Principal uncertainty
Whether processing and ageing change biological, mechanical or sterile-barrier performance.
Critical user moment
The clinician inspects, opens, inserts, connects and disposes of the device.
Define contact, duration and users precisely
The device is intended for single-use peripheral vascular access in adult patients by trained healthcare professionals, for administration of compatible fluids over a specified short-term duration. It is supplied sterile and non-pyrogenic.
Anatomical site, duration, fluids, population, user and environment determine materials, performance, biological evaluation and validation. Apply MTL-102 — Intended Purpose, Users and Use Environments.
Evaluate the finished device, not a material name
Material characterisation covers formulation, additives, colourants, processing aids, adhesives, inks, lubricants and potential residues. Biological evaluation considers the finished, sterilised and aged device in its contact category and duration. Supplier declarations support—but do not replace—the device-specific assessment.
Specify the condition at clinical use
- The catheter shall withstand insertion and claimed use without fracture, leakage, separation or unacceptable deformation.
- The flow path and connections shall meet dimensional, leakage and compatibility requirements.
- The finished device shall meet particulate, residue, biological and pyrogen-related acceptance criteria.
- The sterilisation process shall deliver the specified sterility assurance level without unacceptable product degradation.
- The sterile-barrier system shall remain intact through the claimed shelf life and distribution environment.
- The package shall permit aseptic presentation and visible inspection before use.
- Labelling shall identify single use, sterility, expiry, storage and applicable compatibility limits.
Connect harm to material and process controls
Loss of sterility
Seal or package damage permits microbial ingress. Control materials, sealing, inspection, transport and ageing.
Catheter fracture
Material or process variation weakens the tube. Control formulation, extrusion, dimensions and mechanical testing.
Biological reaction
Extractables or residues cause local or systemic harm. Characterise the finished device and control changes.
Reuse
Cleaning cannot restore validated condition and may damage the device. Design and label for single use and foreseeable behaviour.
Risk controls must be translated into design and process specifications using MTL-114 — Medical-device Risk Management.
Control the manufacturing chain
Incoming materials are verified against controlled specifications. Extrusion and moulding parameters govern critical dimensions and mechanical properties. Bonding and assembly processes prevent occlusion, leakage and separation. Environmental controls protect bioburden and cleanliness. Processes whose output cannot be fully verified later—including sealing and sterilisation—receive validated process controls.
Use MTL-124 — Production-process Validation and MTL-123 — Supplier and Outsourced-process Control.
Test the finished, aged and sterilised device
Functional performance
Dimensions, penetration, flow, leakage, tensile strength, connection and simulated use.
Biological safety
Chemical characterisation, toxicological assessment, biological endpoints and residues.
Sterilisation
Product definition, load configuration, dose or cycle, bioburden, residuals and routine control.
Packaging and shelf life
Seal strength, integrity, ageing, distribution, conditioning, inspection and aseptic presentation.
Follow one sterile-barrier thread
Release the process as part of the product
Transfer defines drawings, material and component specifications, tooling, process parameters, environmental limits, in-process controls, sampling, validated sealing and sterilisation, packaging configuration, acceptance tests and device-history evidence. Release confirms the correct product, load and process combination.
Use a polymer change to test lifecycle control
A supplier discontinues the catheter polymer grade and offers a nominally equivalent formulation. The team must assess composition, additives, processing, dimensions, mechanical performance, extractables, toxicology, sterilisation interaction, ageing, packaging and regulatory impact before approval.
“Equivalent” is a hypothesis requiring proportionate evidence, not a supplier conclusion.
Questions to challenge the case
- Which characteristics are critical at the end of shelf life?
- What evidence represents the finished sterilised device?
- Which manufacturing processes require validation?
- How is the sterile barrier inspected and routinely controlled?
- Which supplier changes require biological reassessment?
- What evidence supports the single-use claim and foreseeable misuse controls?