Diagnosis of Active and Latent Tuberculosis

PRACTICE GUIDELINES Diagnosis of active and latent tuberculosis: summary of NICE guidance Ibrahim Abubakar,1 Chris Griffiths,2 Peter Ormerod,3 on behalf of the Guideline Development Group 1Research Department of Infections Tuberculosis is a major preventable infectious cause of six weeks and repeat the Mantoux test to reduce the and Population Health, University morbidity and mortality globally, which has re-emerged rate of false negative results for latent infection. College London, London 2 in high risk groups such as migrants, homeless people, Centre for Primary Care and Public 1 Health, Queen Mary University of problem drug users, and prisoners in the UK. This arti- Household contacts younger than 2 years and older than London cle summarises the most recent recommendations (2011) 4 weeks 3Royal Blackburn Hospital, from the National Institute for Health and Clinical Excel- • If contact was with a person whose sputum smear is Blackburn, UK lence (NICE)2 on the diagnosis of latent tuberculosis positive for acid fast bacilli: Correspondence to: I Abubakar [email protected] (including the use of new tests) and of active tuberculo- – For children not vaccinated with BCG, perform a Cite this as: BMJ 2012;345:e6828 sis. Although this summary focuses on diagnosis, the full Mantoux test and offer isoniazid doi: 10.1136/bmj.e6828 guidelines cover the public health and clinical manage- – If the Mantoux test is positive, assess the child ment of tuberculosis and replaced the guidelines pub- for active tuberculosis. If active tuberculosis is This is one of a series of BMJ 3 summaries of new guidelines lished in 2006. excluded, offer full treatment for latent infection based on the best available – If the Mantoux test is negative (<6 mm evidence; they highlight important Recommendations induration), continue isoniazid for six weeks, recommendations for clinical practice, especially where NICE recommendations are based on systematic reviews and then repeat the Mantoux test together with uncertainty or controversy exists. of best available evidence and explicit consideration of an IGRA. If the repeat tests are negative, isoniazid Further information about the cost effectiveness. When minimal evidence is available, may be stopped and BCG vaccination performed. guidance, a list of members of the recommendations are based on the Guideline Development If either repeat test is positive, assess the child guideline development group, and the supporting evidence Group’s experience and opinion of what constitutes good for active tuberculosis and consider treating for statements are in the full version practice. Evidence levels for the recommendations are given latent tuberculosis on bmj.com. in italic in square brackets. Evidence levels for the recom- – For vaccinated children, perform a Mantoux test. mendations are in the full version of this article on bmj.com. If the Mantoux reaction is <15 mm, repeat the Mantoux test after six weeks, together with an IGRA. Diagnosing latent tuberculosis (new/updated If both repeat tests are negative, no further action recommendations) is needed. If either test is positive, exclude active All contacts of tuberculosis cases, aged 5 years or older tuberculosis and follow with treatment for latent • Offer Mantoux testing in line with the Department of tuberculosis. Health’s Green Book4 to: – Household contacts of all people with active Contacts in outbreak tuberculosis • If large numbers of individuals need to be screened, – Non-household contacts (other close contacts, such consider a single IGRA for people aged ≥5 years. as in workplaces and schools). • A positive Mantoux test is an induration of ≥6 mm New entrants from countries with a high incidence of diameter for those who have not been vaccinated with tuberculosis BCG and ≥15 mm diameter for those who have been • For children under 5 years, offer a Mantoux test. If vaccinated. strongly positive, refer to consider treating latent • Consider interferon-γ release assay (IGRA) for people tuberculosis. whose Mantoux test shows positive results, or in • For children aged 5–15 years, offer a Mantoux test. If people for whom Mantoux testing may be less reliable positive, follow with an IGRA. (such as those who have been vaccinated with BCG). • For people aged 16–35 years, offer either an IGRA • Refer people with a positive IGRA or an inconclusive alone or a dual strategy (Mantoux test followed by Mantoux test to a tuberculosis specialist. IGRA). • For people over 35 years, consider the individual risks Household contacts aged 2–5 years and benefits of likely subsequent treatment before • Offer Mantoux testing. offering testing. • If the initial test is positive (taking into account BCG vaccination history), refer to a tuberculosis specialist People who are immunocompromised to exclude active disease and consider treating latent • If latent tuberculosis is suspected in children who are tuberculosis. immunocompromised, refer to a tuberculosis specialist. • If the initial Mantoux test is negative but the child is • For people with HIV infection and CD4 counts <200 a contact of a person with disease that is positive for cells/mm3 (<200×106/L), offer concurrent IGRA and acid fast bacilli on a sputum smear, offer an IGRA after Mantoux tests. If either test is positive, perform a BMJ | 3 NOVEMBER 2012 | VOLUME 345 45 PRACTICE bmj.com clinical assessment to exclude active tuberculosis and Active non-respiratory tuberculosis Previous articles in consider treating latent tuberculosis. • Discuss the advantages and disadvantages of both this series • For people with HIV and CD4 counts of 200–500 biopsy and needle aspiration with the patient, with 3 Ж Assessment and cells/mm , offer an IGRA alone or concurrent IGRA the aim of obtaining adequate material for diagnosis. management of psoriasis: and Mantoux tests. If either test is positive, perform a • If non-respiratory tuberculosis is a possibility, place summary of NICE guidance clinical assessment to exclude active tuberculosis and part or all of any of the following samples in a dry pot consider treating latent tuberculosis. (do not place in formalin) and send for tuberculosis (BMJ 2012;345:e6712) • For other people who are immunocompromised, culture: lymph node biopsy, pus aspirated from lymph Ж Prevention and offer an IGRA test alone or concurrent IGRA and nodes, pleural biopsy, any surgical sample sent for management of Mantoux tests. If either test is positive, perform a routine culture, any radiological sample sent for neutropenic sepsis in clinical assessment to exclude active tuberculosis and routine culture, histology sample, aspiration sample, patients with cancer: consider treating latent tuberculosis. autopsy sample. summary of NICE guidance • Microbiology staff should routinely perform (BMJ 2012;345:e5368) Healthcare workers tuberculosis culture on the above samples (even if it is Ж Diagnosis and • Offer a Mantoux test to new NHS employees who will not requested). management of be in contact with patients or clinical materials if the • Take a chest x ray of all patients with non-respiratory headaches in young employees are not new entrants from high incidence tuberculosis to exclude or confirm coexisting people and adults: countries and have not had BCG vaccination (they do respiratory tuberculosis. In addition, consider summary of NICE guidance not have a vaccination scar, other documentation. or imaging, biopsy, and histopathology as well as (BMJ 2012;345:e5765) reliable history). If the Mantoux test is negative, refer bacterial culture depending on the affected organ. Ж Diagnosis and to the Green Book for BCG immunisation guidance. If • If clinical signs and other laboratory findings are management of lower the Mantoux test is positive, offer an IGRA. consistent with tuberculosis meningitis, start limb peripheral arterial • For new NHS employees who have recently arrived treatment, even if a rapid diagnostic test is negative, from high incidence countries or who have had because the potential consequences for the patient are disease: summary of NICE contact with patients in settings where tuberculosis is severe. guidance highly prevalent, offer an IGRA. • Carry out rapid diagnostic tests for M tuberculosis (BMJ 2012;345:e4947) • Screen healthcare workers who are complex on biopsy material only if all the sample has Ж Management of lower immunocompromised in the same way as other people been inappropriately placed in formalin and acid-fast urinary tract dysfunction who are immunocompromised. bacilli are visible on microscopy. in neurological disease: summary of NICE guidance Hard to reach groups Large scale contact investigation (BMJ 2012;345:e5074) • Offer people from hard to reach groups a single IGRA • With a positive result by microscopy or tuberculosis (see NICE guidelines on the control of tuberculosis in culture, confirm the species of mycobacterium to be hard to reach groups5). M tuberculosis complex by rapid diagnostic tests on material before starting large scale contact tracing Diagnosis of active tuberculosis (such as in a school or hospital). Use clinical judgment Active respiratory tuberculosis if tests are inconclusive or delayed. • Take a posterior-anterior chest x ray. If the x ray appearance suggests tuberculosis carry out further Multiple drug resistant (MDR) tuberculosis diagnostic investigation. • Undertake a risk assessment for MDR tuberculosis. • Send multiple sputum samples (at least three, Risk factors for MDR tuberculosis include prior with one early morning sample) for tuberculosis

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