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You are here: Home Services & Applications Data Standards NHS Classifications Service Standards and Audit OPCS-4 Classification Background

Background to OPCS-4 development

Background to enhancing OPCS-4-2 to create OPCS-4.3 and subsequent annual reviews.

OPCS-4 is an abbreviation for the Office of Population, Censuses and Surveys Classification of Surgical Operations and Procedures (4th revision). This statistical classification translates operations and surgical procedures into codes.

OPCS-4 is a mandatory NHS data standard, and its output forms part of the data flows for Commissioning Data Sets and national Hospital Episode Statistics (HES).

Click here for more detailed background and history of OPCS-4 in the NHS.

Reviewing classification

Classifications like OPCS-4 and ICD-10 must be reviewed continuously to ensure they evolve with NHS policy, changing healthcare provisions, and the coding structures used in electronic health records. Working closely with the clinical community, we have recently issued updates to OPCS-4 which is now on an annual review cycle.


SNOMED CT is the agreed national standard for recording clinical information in patient records.

SNOMED CT will be enhanced to provide a single coherent coding system to provide a clinical terminology that will support the needs of a classification and associated secondary uses.

Classification materials

Classification literature is split into chapters which cover each part of the anatomy (relating to the whole or part of a system of the body).

Classification conventions

Coding rules and conventions ensure that data can be recorded in a consistent and comparable fashion – on local, national and international levels. National clinical coding standards and guidance are published on our Coding Clinic publication. This guidance is agreed by the UK Coding Review Panel and is incorporated as data standards in the NHS Clinical Coding Instruction Manual ICD-10 and OPCS-4.


OPCS-4 is Crown copyright. NHS Connecting for Health is responsible for administrating and maintaining OPCS-4, as well as issuing licence agreements.