From the Guidelines
In the UK, high-risk groups including recent arrivals from high TB prevalence countries, close contacts of active TB cases, immunocompromised individuals, healthcare workers, homeless people, prison inmates, and those with a history of TB or substance abuse should be screened for tuberculosis using a combination of methods, primarily the Interferon-Gamma Release Assay (IGRA) blood test or the Tuberculin Skin Test (Mantoux test), followed by chest X-rays for those with positive results. The screening approach in the UK is guided by the need to balance the risk of TB transmission with the practicality and cost-effectiveness of screening, as outlined in studies such as 1 and 1. Key groups recommended for screening include:
- Recent arrivals from high TB prevalence countries, particularly those from sub-Saharan Africa, Asia, and Eastern Europe
- Close contacts of active TB cases
- Immunocompromised individuals, including HIV-positive people
- Healthcare workers
- Homeless people
- Prison inmates
- Those with a history of TB or substance abuse The primary screening tools are:
- Interferon-Gamma Release Assay (IGRA) blood test
- Tuberculin Skin Test (Mantoux test) Those with positive results undergo further evaluation with:
- Chest X-rays to look for signs of active TB
- Symptomatic individuals may also provide sputum samples for microscopy, culture, and molecular testing For latent TB infection, preventive treatment typically consists of either rifampicin plus isoniazid for three months or isoniazid alone for six months, as suggested by 1. This targeted screening approach is essential because early detection allows for prompt treatment, preventing progression to active disease and reducing transmission within communities, as emphasized in 1 and 1. The UK's selective screening strategy focuses resources on those most likely to benefit, as universal screening would be impractical and cost-ineffective in a low TB incidence country.
From the Research
Screening for Tuberculosis in the UK
The UK has a low incidence of tuberculosis (TB), but the disease still poses a significant public health risk, particularly among migrant populations. To control the spread of TB, the UK has implemented screening programs for individuals from high-incidence countries.
Who Should be Screened
According to studies 2, 3, 4, the following individuals should be screened for TB:
- Migrants from high-incidence countries who intend to stay in the UK for more than 6 months
- Individuals who have had close contact with someone with TB
- Those who have been born or lived in countries with high TB incidence
- People who have been in prison or have a history of drug or alcohol abuse
- Individuals with certain medical conditions, such as HIV/AIDS or diabetes
Screening Methods
The most commonly used screening methods for TB in the UK are:
- Chest radiograph (X-ray) to detect any abnormalities in the lungs
- Sputum testing and culture to detect the presence of Mycobacterium tuberculosis
- Interferon-gamma release assay (IGRA) to detect latent TB infection
- Tuberculin skin test (TST) to detect latent TB infection
Implementation of Screening Programs
Studies 5, 4 have shown that screening programs can be implemented effectively in various settings, including:
- Pre-entry screening for migrants before they arrive in the UK
- Community-based screening programs, such as those conducted in colleges or community centers
- Primary care settings, such as general practitioner surgeries
Risk Factors for TB
Research has identified several risk factors for TB, including:
- Country of origin, with higher incidence rates in certain countries 2, 3, 4
- Age, with higher incidence rates in younger individuals 4
- Sex, with higher incidence rates in males 4
- Close contact with someone with TB 3
- Certain medical conditions, such as HIV/AIDS or diabetes 6
Cost-Effectiveness of Screening
Studies 4 have shown that screening for latent TB infection can be cost-effective, particularly in individuals from high-incidence countries. The cost-effectiveness of screening depends on various factors, including the incidence of TB in the individual's country of origin and the cost of screening and treatment.