This study is focused upon early diagnosis, referral and treatment of latent tuberculosis (LTBI), which has two key purposes:
1) preventing individuals from getting active tuberculosis (TB);
2) contributing to disease control in public health terms by preventing further spread.
Accident and Emergency (A&E) Departments are an important point of testing and referral for hospital attendees who constitute those at greatest risk of active tuberculosis, as for many this will be their only interaction with the health service. Currently, about 20% of patients with TB are diagnosed in A&E Departments. The majority of these individuals are more likely to have presented with symptoms indicative of TB disease, compared to those attending for other reasons who would have been unlikely to have been tested or referred. Similarly, many individuals at risk of LTBI would only have contact with an A&E department and not other parts of the health system. There are therefore potential missed opportunities to diagnose latent and active tuberculosis among high-risk individuals in A&E departments.
The ACE study seeks to evaluate specific measures currently being undertaken by Public Health England and the NHS to control TB, as well as investigate whether case finding for active TB in A&E departments would improve TB control (see separate protocol for ACE active TB). This study is linked by the NIHR funded PREDICT study (Prognostic value of Interferon Gamma Release Assays in predicting active tuberculosis among individuals with, or at risk of, latent tuberculosis infection). The economic impact of these interventions will be evaluated, providing a measure of their value for money.