NHS Connecting for Health ceased to exist on 31st March 2013. This website is therefore not being updated. For up to date information about systems and services visit the Health and Social Care Information Centre website at www.hscic.gov.uk/systems

You are here: Home Services & Applications Pseudonymisation

Pseudonymisation Implementation Project


Pseudonymisation is concerned with enabling the NHS to undertake secondary use of patient data in a legal, safe and secure manner.

The overall aim of implementing pseudonymisation is to facilitate:

  • The legal and secure use of patient data for secondary purposes by the NHS (and other organisations involved in the commissioning and provision of NHS-commissioned care)
  • NHS business to no longer use identifiable data in its non-direct care related work wherever possible
  • NHS business processes to continue to be effective in supporting the day-to-day operation of the NHS.

Legal Requirements

It is a legal requirement that when patient data is used for purposes not involving the direct care of the patient, i.e. Secondary Uses, the patient should not be identified unless other legal means hold, such as the patient's consent or Section 251 approval. This is set out clearly in the NHS policy and good practice guidance document 'Confidentiality: the NHS Code of Practice', which states the need to 'effectively anonymise' patient data prior to the non-direct care usage being made of the data.

Data cannot be labelled as primary or secondary use data - it is the purpose of the disclosure and the usage of the data that is either primary or secondary. This means that even where it is justifiable to hold data in identifiable form,  it becomes essential to ensure that only authorised users are able to have identifiable data disclosed to them.

NHS Organisation Implementation

The implementation of pseudonymisation to support secondary uses in NHS organisations is based on each local organisation undertaking its own pseudonymisation as appropriate.

This approach supports the increasing number of direct information flows between providers and commissioners necessary for NHS business operations. It requires that organisations continually review and modify, where necessary, aspects of their management of and user access to identifiable and pseudonymised data as well as business processes, end user applications and the relevant logging and auditing facilities.

Implementation Assurance

Requirements relating to the protection and confidentiality of service user information through the use of pseudonymisation and anonymisation techniques are covered within the Information Governance Toolkit.

Organisations are required to carry out self-assessments of their compliance against the Information Governance requirements using the online assessment that is part of the Toolkit.

NHS regulatory bodies use the Toolkit to assess the performance of NHS organisations.  Members of the public are also able to use the Toolkit to access reports of an organisations assessment.

See the Information Governance Toolkit website for further details and information.

Queries and Further Information

Any questions relating to pseudonymisation policy should be directed through the 'Contact Us' link available on the Information Governance Toolkit website.

For any other queries please send an email to PIP@nhs.net and the team will try to provide an initial response within one week.

Additional supporting guidance is also available as follows: