End-to-End Traceability for Combo Products: From User Needs to Design Validation

18 Sep 2026

In combination product development, a requirement can easily become separated from the evidence that is supposed to demonstrate that it has been met. A user need may be defined by one team, converted into a design input by another, addressed through a risk control, and finally tested by an engineering or laboratory team.

The important question is: Can the organization still show the complete connection?

This is where traceability becomes important. For drug-device combination products, traceability connects user needs, design inputs, risks, design outputs, verification and validation. It provides a structured way to demonstrate that the product being developed is the product that was actually required.

What Is End-to-End Traceability?

Traceability is the ability to follow the relationship between requirements and the evidence generated throughout product development.

For a combination product, a simplified traceability chain can be:

User Needs → Design Inputs → Risk Controls → Design Outputs → Verification → Validation

The relationship should work in both directions. If an auditor asks, “Which test demonstrates this requirement has been met?”, the relevant evidence should be easy to identify.

Similarly, if a verification test fails, the development team should be able to determine which requirement, risk or design feature may be affected. Traceability is therefore more than maintaining a spreadsheet. It is a method for keeping the development process connected and controlled.

Why is traceability important for Combination Products?

Combination products can involve pharmaceutical, device, biological, human-factors and manufacturing considerations. These areas may be managed by different functions, which increases the possibility of requirements becoming disconnected.

Consider a prefilled syringe. Development may involve requirements for:

• dose accuracy;
• injection force;
• material compatibility;
• container-closure integrity;
• usability;
• stability; and
• packaging.

Some requirements relate mainly to the device, some to the drug, and others arise because the two are being used together. Traceability helps ensure that these requirements are not managed as isolated activities.

How to Build End-to-End Traceability

1. Start With User Needs

Traceability should begin with what the product is intended to achieve for its users and patients.

For example:

User need: The patient should be able to administer the prescribed dose safely and correctly.

This is a high-level requirement. It needs to be translated into specific and measurable requirements before engineering can demonstrate conformity.

The user need should therefore have a clear relationship with the relevant design inputs.

2. Translate User Needs Into Design Inputs

Design inputs convert user expectations into specific requirements.

For example:

User need: The patient should receive the intended dose.

Design input: The delivery system shall deliver the specified dose within the defined acceptance range under specified operating conditions.

One user need can generate several design inputs.

This relationship is important because validation addresses whether the finished product meets user needs, while verification determines whether design outputs meet specified design requirements.

The traceability system should make this relationship visible rather than leaving it to individual team members to remember.

3. Connect Requirements to Risk Management

Design requirements should also be connected to risk management.

Suppose incorrect dose delivery has been identified as a potential hazardous situation. The risk-control strategy may include a mechanical feature, software control, dimensional requirement or specific testing requirement.

The traceability should make this relationship visible.

The organization should be able to answer:

Which requirement addresses this risk?

And then:

Which verification or validation activity demonstrates that the risk control is effective?

This becomes particularly important when a risk results from the interaction between the drug and device.

4. Connect Design Outputs

Design outputs represent what has actually been developed from the approved requirements.

Depending on the product, these may include drawings, specifications, software requirements, material specifications, packaging requirements and manufacturing information.

Traceability should demonstrate that important design outputs address the applicable design inputs.

If a critical design input has no corresponding design output, there may be a development gap.

Conversely, if an important design feature appears without a clear requirement or rationale, the organization should understand why it exists and how it is controlled.

5. Link Requirements to Verification

One of the most important purposes of traceability is to connect requirements with objective verification evidence.

For example:

Not every requirement requires one separate test. One test may verify several requirements, while one requirement may require multiple tests.

The important point is that the relationship should be defined and justified.

A requirement without appropriate verification evidence creates a traceability gap.

6. Link User Needs to Validation

Verification and validation should not be treated as the same activity.

A useful practical distinction is:

Verification: Did the design meet the specified requirements?

Validation: Does the finished product meet the intended user needs and intended use?

For example, an autoinjector may be verified to deliver the required dose and operate within its specified force range. However, validation may need to establish whether intended users can correctly use the finished product under representative conditions.

The traceability system should therefore show the connection between user needs and validation evidence.

This distinction is especially important for combination products where usability, intended use and actual product performance must come together.

7. Control Design Changes

Requirements and designs can change throughout development.

A material may be replaced. A device component may change. A design input may be revised. A risk assessment may identify an additional control.

When this happens, traceability helps determine the downstream impact.

The organization should be able to identify:

What requirement changed?

Which risk is affected?

Which design output must be updated?

Does verification or validation need to be repeated?

Without traceability, a change can be implemented in one document while its consequences remain unnoticed elsewhere.

8. Review the Matrix for Gaps

A traceability matrix should not be created only at the end of development for an audit. It should be reviewed throughout development.

A traceability gap occurs when a requirement has no appropriate evidence linked to it.

An orphan test occurs when a test cannot be clearly connected to a relevant requirement.

The purpose is not to create the largest possible matrix. The purpose is to create a useful and controlled representation of the relationships within the development process.

What Should the Traceability Matrix Contain?

The exact structure depends on the product, but a combination-product traceability matrix may include:

• User Need ID
• Design Input ID
• Risk/Control ID
• Design Output ID
• Verification Test ID
• Validation Test ID
• Requirement status
• Test status
• Change reference, where applicable

For complex products, additional levels may be required for subsystem requirements, software, manufacturing processes or drug-device interfaces.

The matrix should also remain synchronized with the controlled design documentation. A matrix that says one thing while the current design documents say something else can create more confusion than traceability.

Benefits of Good Traceability

Effective traceability provides practical benefits throughout development.

It helps identify missing requirements, demonstrate that requirements have been tested, assess the impact of design changes and prepare objective evidence for regulatory review.

It also improves communication between engineering, quality, regulatory, pharmaceutical development, human factors and manufacturing teams.

Most importantly, traceability provides confidence that development has remained connected from the original user need through to the final evidence.

How TS Quality & Engineering Can Help

End-to-end traceability is not about creating more paperwork. It is about maintaining the connection between what the user needs, what the organization designed, what risks were controlled, and what evidence demonstrates that the product works as intended.

For drug-device combination products, this connection is important because requirements and risks can cross pharmaceutical, device, human-factors and manufacturing boundaries. A well-maintained traceability system makes these relationships visible and helps the organization identify gaps, evaluate changes and demonstrate objective evidence.

TS Quality & Engineering (TSQE) supports drug-device combination product development through practical expertise in design controls, requirements management, traceability, risk management, design verification and validation, human factors and technical documentation. TSQE can help organizations establish a structured traceability approach from user needs through design inputs, risks, design outputs and V&V evidence, supporting a connected and inspection-ready development process.

References

Hamadeh, A. (n.d.) Traceability in Systems Engineering (Medical Devices Focus). Available at: LinkedIn article (Accessed: 14 September 2026).