New registrations with primary care.
Entry to education (including universities).
Links with statutory and voluntary groups working with new entrants.
Neonatal BCG vaccination for any baby at increased risk of TB should be discussed with the parents or legal guardian. Primary care organisations with a high incidence of TB should consider vaccinating all neonates soon after birth.
Screening is done using either an intradermal Mantoux (skin) test injected into the skin of the inner surface of the forearm, or an interferon gamma release assay (IGRA) blood test.
Public Health England recommends that IGRA tests should not be used as a routine diagnostic tool for active TB and only considered in supporting the primary diagnosis of active TB when it has not been possible to confirm the diagnosis by culture and when strong support for the diagnosis is lacking from radiological and histopathological tests. If the diagnosis remains in doubt and a subsequent management decision on whether or not to treat will be influenced by the result, then the use of IGRA test is supported. The final decision should be based on clinical judgement. The diagnosis of active TB is rarely made from the result of any one single test.
The National Institute for Health and Care Excellence (NICE) recommends IGRA testing for people whose Mantoux test shows positive results, or in people for whom Mantoux testing may be less reliable - eg, BCG-vaccinated people.
Aged 2-5 years: offer Mantoux test and, if positive, refer to a TB specialist for exclusion of active TB and possible treatment of LTBI. If Mantoux test is negative (but the child is a contact of sputum-smear-positive disease), offer IGRA after six weeks and repeat the Mantoux test to increase the sensitivity (to reduce false negative results).
Aged ≥5 years: offer Mantoux test and consider IGRA if Mantoux-positive results, or where Mantoux testing may be less reliable - for example, BCG-vaccinated people. If Mantoux testing is inconclusive, refer the person to a TB specialist.
Children aged under 2 years require anti-TB treatment - see the NICE guidance.
Aged under 5 years: offer Mantoux test and, if positive, refer to a TB specialist for exclusion of active TB and possible treatment of LTBI.
Aged 5-15 years: offer Mantoux test; follow with IGRA if positive.
Aged 16-35: offer IGRA alone or (dual strategy, ie following Mantoux test).
If aged 35 years, consider the individual risks and benefits of likely subsequent treatment, before offering testing.
Children: refer to a specialist if infection is suspected.
Adults: perform IGRA ± Mantoux and, if either is positive, assess for active disease and consider treatment for latent infection. For people with HIV and CD4 counts less than 200 cells/mm3 performing both Mantoux testing and IGRA is recommended.
Those who have not had a BCG vaccination: screen with Mantoux test and vaccinate with BCG if negative.
NHS employees who have recently arrived from high-incidence countries or who have had contact with patients in settings where TB is highly prevalent: offer IGRA.
Hard to reach groups: - offer a single IGRA.
Skin testing can detect previous exposure to the organism (or BCG vaccination) by provocation of a well-established, cell-mediated immune reaction. A purified protein derivative (PPD) of Mycobacterium tuberculosis is injected intradermally into the flexor surface of the forearm and the local response is measured. The interpretation of tuberculin tests depends on BCG vaccination history, immune status and concurrent viral infection.
As an aid to the clinical diagnosis of TB infection (10 TU/0.1 ml).
The local skin reaction to tuberculin PPD injected into the skin is used to assess an individual's sensitivity to tuberculin protein. The greater the reaction, the more likely it is that an individual is infected or has active TB disease.Precise interpretation depends on whether it is being used for screening or clinical diagnostic purposes.
Measurement in millimeters of the induration.
A person's risk of being infected with TB and of progression to disease if infected.
Less than 5 mm Negative - (no significant hypersensitivity to tuberculin protein).
Previously unvaccinated individuals may be given BCG provided there are no contra-indications.
Suggests no TB infection but beware false negatives.
5 mm or greater Positive - (hypersensitive to tuberculin protein).
A recent contact of a person with TB disease.
Persons with fibrotic changes on chest radiograph consistent with prior TB.
Persons who are immunosuppressed for other reasons (eg, taking the equivalent of >15 mg/day of prednisone for one month or longer, taking TNF-antagonists).
10 mm or greater Strongly positive - (strongly hypersensitive to tuberculin protein).
Recent immigrants (<5 years) from high-prevalence countries.
Residents and employees of high-risk congregate settings.
Persons with clinical conditions that place them at high risk.
Children <4 years of age.
Infants, children, and adolescents exposed to adults in high-risk categories.
15 mm or greater Strongly positive - (strongly hypersensitive to tuberculin protein).
An induration of 15 or more millimetres considered positive in any person, including persons with no known risk factors for TB. However, targeted skin testing programmes should only be conducted among high-risk groups.
Cutaneous anergy (anergy is the inability to react to skin tests because of a weakened immune system).
Recent TB infection (within 8-10 weeks of exposure).
Very old TB infection (many years).
Very young age (less than 6 months).
Recent live-virus vaccination (eg, measles and smallpox).
Some viral illnesses (eg, measles and chickenpox).
Incorrect method of test administration.
Either on the same day as vaccination with live-virus vaccine or 4-6 weeks after the administration of the live-virus vaccine.
At least one month after smallpox vaccination.
The Heaf's test is no longer recommended in the UK where it was used for larger less targeted screening programmes (it used a six-pointed apparatus to deliver the solution, and the degree of induration at the puncture site was measured 3-10 days later).
Professionals at risk of TB (eg, healthcare workers).
Close contacts of patients with TB (if active TB is suspected).
This should be carried out by the multidisciplinary TB team. Detailed guidance has been outlined by NICE.
It aims to detect people infected with TB but with no clinical evidence of disease (10% of all TB diagnoses).
It aims to identify BCG vaccination candidates.
It aims to detect a source patient - eg, when a child is diagnosed with TB.
Screening is recommended for selected contacts, since the source case has exhibited respiratory symptoms. If this is unknown, contacts during the three months preceding the initial diagnosis are screened. Tracing should be extended backwards if necessary.
Initially, screen people from the same household and any frequent visitors of the index case. If the index case has pulmonary TB, all close contacts should be screened. Screening is not usually necessary for contacts of non-pulmonary TB patients.
Screening of casual contacts is less fruitful and is only necessary if the index case is highly infectious or the contacts are particularly susceptible, such as young children or immunocompromised adults. Casual contacts include occupational contacts or healthcare workers.
Tuberculous disease: ie a positive skin test with clinical signs and symptoms. Begin one of the standard treatment regimens.
Latent tuberculous infection: ie a positive skin test but asymptomatic and normal CXR, suggesting presence of small numbers of bacteria in the body, which may later cause disease.
See the separate article on Tuberculosis for treatment of LTBI.
BCG immunisation should be offered to all previously unvaccinated tuberculin-negative individuals under 16 years of age who are contacts of cases of respiratory TB.See also the separate article on BCG Vaccination.
Zenner D, Southern J, van Hest R, et al; Active case finding for tuberculosis among high-risk groups in low-incidence countries. Int J Tuberc Lung Dis. 2013 May17(5):573-82. doi: 10.5588/ijtld.12.0920.