CTAD Chlamydia Surveillance System
Source: gov.uk (2025-01-09)

Guidance on the collection and reporting of data for CTAD, the surveillance system for all chlamydia tests done in England.

About

The CTAD Chlamydia Surveillance System is the new name for the Chlamydia Testing Activity Dataset (CTAD).

CTAD Chlamydia Surveillance System data is used to provide detailed reports at national and local levels on screening coverage, the proportion of chlamydia tests that are positive and the chlamydia detection rate in England.

UK Health Security Agency (UKHSA) uses chlamydia data combined from the CTAD Chlamydia Surveillance System and the GUMCAD STI Surveillance System (https://www.gov.uk/guidance/genitourinary-medicine-clinic-activity-dataset-gumcadv2) to report chlamydia testing activity.

CTAD became mandatory in April 2012, replacing the NCSP and the non-NCSP non-GUM (NNNG) data sources of chlamydia data from non-specialist sexual health services (SHSs). These changes mean that data for 2012 onwards are not directly comparable with the data reported in earlier years.

Resources

Technical guidance and dataset specifications for laboratories submitting data in compliance with the Standardisation Committee for Care Information (SCCI).

CTAD specification and technical guidance (https://www.gov.uk/government/publications/chlamydia-testing-activity-dataset-ctad-specification-and-technical-guidance)

Commissioning laboratory testing

UKHSA encourages commissioners, providers and laboratories to work together to ensure that the data for local CTAD returns are complete. UKHSA has developed information and other resources to help the commissioning of chlamydia activity data collection.

CTAD commissioning guidance, 2015 update (https://www.gov.uk/government/publications/ctad-commissioning-guidance)

CTAD data quality

As with any surveillance system, CTAD data quality is vital. Reporting high quality data through CTAD is key to informing local sexual health service planning, assessing the impact of the National Chlamydia Screening Programme (NCSP) (https://www.gov.uk/government/collections/national-chlamydia-screening-programme-ncsp) and monitoring progress towards the Public Health Outcomes Framework chlamydia diagnosis rate indicator.

The CTAD data validation process identified 2 main issues that affect local authority level chlamydia data:
- postcode of residence to ensure tests and diagnoses are assigned to the correct local authority
- testing service type to minimise double-counting between CTAD and GUMCAD and to correctly monitor testing carried out in different settings
Improving data accuracy and completeness will improve the quality of data for different service types.

CTAD data resubmission

Laboratories are encouraged to resubmit CTAD data for any period (including 2012) to the HIV and STI Web Portal (https://hivstiwebportal.phe.org.uk/) when there has been an improvement in the data quality and completeness since the original submission. This data will be available to registered portal users. Any data resubmitted will be reflected in the next annual data release.

Important points to note:
- resubmissions of data will overwrite any previous submissions received
- as usual, any updates to data must be submitted as a quarter (specifically files for individual quarters must be uploaded, rather than one file for multiple quarters)
- labs should inform the CTAD team they intend to resubmit updated retrospective data, prior to uploading it
Submission and reporting deadlines

Resubmissions can be done anytime, please contact CTAD (mailto:xxx@xxx.xx) in advance.

Accessing CTAD data

Information on chlamydia and service provision in England is available on:
- STIs and screening for chlamydia in England annual report, NCSP data tables, infographic and slide set (https://www.gov.uk/government/statistics/national-chlamydia-screening-programme-ncsp-data-tables) at national and regional level
- chlamydia re-testing following a positive diagnosis (https://www.gov.uk/government/publications/chlamydia-re-testing-following-a-positive-diagnosis) report
Information and guidance on sexual and reproductive health at national and local authority level is available on:
- Sexual and Reproductive Health Profiles (http://fingertips.phe.org.uk/profile/sexualhealth) for interactive maps, charts and tables
- Sexual health, reproductive health and HIV in England: a guide to local and national data (https://www.gov.uk/government/publications/sexual-and-reproductive-health-in-england-local-and-national-data) for guidance to help health professionals understand the sexual health data available across England and how to access it
- Wider Impacts of COVID-19 on Health (WICH) monitoring tool (https://analytics.phe.gov.uk/apps/covid-19-indirect-effects/) is designed to allow you to explore the indirect effects of the COVID-19 pandemic on the population’s health and wellbeing
Restricted-access reports for monitoring local, regional and national sexual health priorities are available on the HIV and STI Web Portal (https://hivstiwebportal.phe.org.uk/) (registered NHS and local authority users only):
- local authority STI and HIV epidemiology reports
- GUMCAD STI diagnoses and services reports
- CTAD data quality reports
- NCSP quarterly data tables
- chlamydia re-testing following a positive diagnosis report
The principles for accessing, storing and sharing CTAD data is given in the UKHSA HIV and STI data publication guidelines (https://www.gov.uk/government/publications/hiv-and-sti-data-sharing-policy).

Guidance on data submission requirements for services providing self-sampling tests for sexually transmitted infections (STIs).

GUMCAD and CTAD data submission for STI self-sampling services (https://www.gov.uk/government/publications/gumcad-and-ctad-data-submission-for-sti-self-sampling-services)

CTAD data requests

CTAD data can be requested by completing the CTAD data request form (https://www.gov.uk/government/publications/ctad-data-request-form) and sending this to xxx@xxx.xx (mailto:xxx@xxx.xx)

The data team will aim to provide the data within 2 weeks but this may be longer during busier periods such as after the annual data release.

UKHSA sexual health and HIV privacy information

The sexual health and HIV privacy information (https://www.gov.uk/government/publications/ukhsa-sexual-health-and-hiv-privacy-information) guidance explains the de-personalised data we collect, how we use it and how we protect this information.

Changes since 2012 in the chlamydia data

Since the Information Standard (ISB 1538) was approved in 2011 by the Information Standards Board for Health and Social Care (ISB), a number of amendments to the dataset are required to reflect changes in health boundaries and service delivery and improve data quality. This Information Standard has been revised to include one new item, an additional coding option within an existing item and retirement of one item. In addition, there are some minor changes to the NHS Data Dictionary coding options to 2 existing data items. These changes have now been accepted by the Standardisation Committee for Care Information (SCCI) – the standard is SCCI1538 (https://digital.nhs.uk/data-and-information/information-standards/information-standards-and-data-collections-including-extractions/publications-and-notifications/standards-and-collections/scci1538-chlamydia-testing-activity-dataset).

Contact information

For further information, including access permission to the HIV and STI Web Portal (https://hivstiwebportal.phe.org.uk), contact the CTAD helpdesk at xxx@xxx.xx (mailto:xxx@xxx.xx)