National Institute for health and care excellence has released guidelines for Latent TB. It is an update on the guidelines published in January 2016
B. Latent TB
1. Diagnosing latent TB in adults
- Offer Mantoux testing to diagnose latent TB in adults aged 18 to 65 who are close contacts of a person with pulmonary or laryngeal TB.
- If the Mantoux test is inconclusive, refer the person to a TB specialist.
- If the Mantoux test is positive (an induration of 5 mm or larger, regardless of BCG history) assess for active TB.
- If the Mantoux test is positive but a diagnosis of active TB is excluded, consider an interferon gamma release assay if more evidence of infection is needed to decide on treatment. This could be, for example, if the person needs enhanced case management or if there could be adverse events from treatment.
- If the Mantoux is positive, and if an IGRA was done and that is also positive, offer them treatment for latent TB infection. [2011, amended 2016]
Adults who are immunocompromised
- In adults who are anticipated to be or are currently immunocompromised, do a risk assessment to establish whether testing should be offered, taking into account their:
- risk of progression to active TB based on how severely they are immunocompromised and for how long they have been immunocompromised
- risk factors for TB infection, such as country of birth or recent contact with an index case with suspected infectious or confirmed pulmonary or laryngeal TB. [new 2016]
- For adults who are severely immunocompromised, such as those with HIV and CD4 counts of fewer than 200 cells/mm3, or after solid organ or allogeneic stem cell transplant, offer an interferon‑gamma release assay and a concurrent Mantoux test.
- If either test is positive (for Mantoux, this is an induration of 5 mm or larger, regardless of BCG history), assess for active TB.
- If this assessment is negative, offer them treatment for latent TB infection. [new 2016]
- For other adults who are immunocompromised, consider an interferon‑gamma release assay alone or an interferon‑gamma release assay with a concurrent Mantoux test.
- If either test is positive (for Mantoux, this is an induration of 5 mm or larger, regardless of BCG history), assess for active TB.
- If this assessment is negative, offer them treatment for latent TB infection. [new 2016]
Healthcare workers
- Offer a Mantoux test to new NHS employees who will be in contact with patients or clinical materials, if the employees:
- are not new entrants from high‑incidence countries and
- have not had BCG vaccination (for example, they are without a BCG scar, other documentation or a reliable history).If the Mantoux test is positive, offer an interferon‑gamma release assay. If this is positive, assess for active TB; if this assessment is negative, offer them treatment for latent TB infection. [2011, amended 2016]
- Offer a Mantoux test to new NHS employees who are from a high‑incidence country.
- If the Mantoux test is positive (5 mm or larger, regardless of BCG history), assess for active TB; if this assessment is negative, offer them treatment for latent TB infection.
- If Mantoux testing is unavailable, offer an interferon‑gamma release assay. [new 2016]
- Offer an interferon‑gamma release assay to new NHS employees who have had contact with patients in settings where TB is highly prevalent:
- If the interferon‑gamma release assay is positive, assess for active TB and
- if this assessment is negative, offer them treatment for latent TB infection. [2011, amended 2016]
- Healthcare workers who are immunocompromised should be screened in the same way as other people who are immunocompromised. [2011]
2. Diagnosing latent TB in children and young people
- Only consider using interferon‑gamma release assays alone in children and young people if Mantoux testing is not available or is impractical. This includes for example, situations in which large numbers need to be tested. [new 2016]
- Refer children younger than 2 years and in close contact with people with smear‑negative pulmonary or laryngeal TB to a specialist to determine what testing strategy for latent TB should be done. This should be a paediatrician with experience and training in TB, or a general paediatrician with advice from a specialised clinician. [new 2016]
- If a neonate has been in close contact with people with smear‑positive pulmonary or laryngeal TB who have not had at least 2 weeks of anti‑TB treatment:
- Assess for active TB.
- Start isoniazid (with pyridoxine).
- Carry out a Mantoux test after 6 weeks of treatment.
- If the Mantoux test is inconclusive, refer the child to a TB specialist.
- If the Mantoux test is positive (5 mm or larger, regardless of BCG history), reassess for active TB; if this assessment is negative, continue isoniazid (with pyridoxine) for a total of 6 months.
- If the Mantoux test is negative, reassess for active TB and consider an interferon‑gamma release assay:
- if the interferon‑gamma release assay is negative then stop isoniazid (and pyridoxine) and give a BCG vaccination.
- if the interferon‑gamma release assay is positive, reassess for active TB; if this assessment for active TB is negative, continue isoniazid (with pyridoxine) for a total of 6 months. [new 2016]
- If a child aged between 4 weeks and 2 years has been in close contact with people with smear‑positive pulmonary or laryngeal TB who have not had at least 2 weeks of anti‑TB treatment:
- Assess for active TB.
- Start treatment for latent TB and carry out a Mantoux test.
- If the Mantoux test is inconclusive, refer the child to a TB specialist.
- If the Mantoux test is positive (5 mm or larger, regardless of BCG history), reassess for active TB; if this assessment is negative, complete treatment for latent TB.
- If the Mantoux test is negative, continue treatment for latent TB, reassess for active TB after 6 weeks and repeat the Mantoux test:
- if the Mantoux test is negative, consider an interferon‑gamma release assay
- if the interferon‑gamma release assay is negative, treatment for latent TB may be stopped; give a BCG vaccination if the child has not already had one
- if either test is positive, reassess for active TB; if this assessment is negative, complete treatment for latent TB. [new 2016]
- If a child or young person aged between 2 and 17 years has been in close contact with people with pulmonary or laryngeal TB:
- Offer Mantoux testing.
- If the Mantoux test is inconclusive, refer the child or young person to a TB specialist.
- If the Mantoux test is positive (5 mm or larger, regardless of BCG history), assess for active TB; if this assessment is negative, offer them treatment for latent TB infection.
- If the initial Mantoux test is negative, offer an interferon‑gamma release assay after 6 weeks and repeat the Mantoux test. [new 2016]
Immunocompromised children and young people
- If latent TB is suspected in children and young people who are anticipated to be or are currently immunocompromised (for example, if they are from a high incidence country or have been in close contact with people with suspected infectious or confirmed pulmonary or laryngeal TB), refer to a TB specialist. [2016]
3. Diagnosing latent TB in all age groups
New entrants from high‑incidence countries
- Offer Mantoux testing as the initial diagnostic test for latent TB infection in people who have recently arrived from a high‑incidence country who present to healthcare services. If the Mantoux test is positive (5 mm or larger, regardless of BCG history):
- assess for active TB and
- if this assessment is negative, offer them treatment for latent TB infection.If Mantoux testing is unavailable, offer an interferon‑gamma release assay. [new 2016]
Contacts – incident situation
- In an incident situation when large numbers of people may need to be screened, consider a single interferon‑gamma release assay for people aged 18–65 years. For children and young people. [2011, amended 2016]
Under‑served groups
- Offer people younger than 65 years from under-served groups a single interferon‑gamma release assay. [2011, amended 2016]
- Substance misuse services with access to an interferon‑gamma release assay should provide testing for people younger than 65 years who misuse substances if they:
- live in a high incidence area
- are likely to be involved with substance misuse services or other support services on a regular basis (for example, for opioid substitution therapy), when support should be available for directly observed preventive therapy. [2012, amended 2016]
- In high incidence areas (and at prisons that receive prisoners from high incidence areas), prison health services should offer an interferon‑gamma release assay for TB to inmates younger than 65 years who are in regular contact with substance misuse services or other support services. This is provided arrangements have been made for this support to continue after release. [2012, amended 2016]
- Substance misuse services and prison health services should incorporate interferon‑gamma release assay testing with screening for hepatitis B and C and HIV testing. They should refer prisoners and people who misuse substances with positive interferon‑gamma release assays to local multidisciplinary TB teams for further clinical investigations. For prisoners, these investigations should be done in prison if practically possible. [2012, amended 2016]
- If the interferon‑gamma release assay is positive, assess for active TB; if this assessment is negative, offer them treatment for latent TB infection. [new 2016]
4. Managing latent TB in all age groups
- Be aware that certain groups of people with latent TB are at increased risk of going on to develop active TB, including people who:
- are HIV‑positive
- are younger than 5 years
- have excessive alcohol intake
- are injecting drug users
- have had solid organ transplantation
- have a haematological malignancy
- are having chemotherapy
- have had a jejunoileal bypass
- have diabetes
- have chronic kidney disease or receive haemodialysis
- have had a gastrectomy
- are having treatment with anti-tumor necrosis factor‑alpha or other biologic agents
- have silicosis. [new 2016]
- For people, including those with HIV, aged younger than 65 years with evidence of latent TB who have been in close contact with people who have suspected infectious or confirmed active pulmonary or laryngeal drug‑sensitive TB, offer either of the following drug treatments:
- 3 months of isoniazid (with pyridoxine) and rifampicin or
- 6 months of isoniazid (with pyridoxine). [new 2016]
- Base the choice of regimen on the person's clinical circumstances. Offer:
- 3 months of isoniazid (with pyridoxine) and rifampicin to people younger than 35 years if hepatotoxicity is a concern after an assessment of both liver function (including transaminase levels) and risk factors
- 6 months of isoniazid (with pyridoxine) if interactions with rifamycins are a concern, for example, in people with HIV or who have had a transplant. [new 2016]
- Clearly explain the risks and potential benefits of each treatment regimen. In discussion with the person, select a suitable regimen if they wish to proceed with preventive treatment. [new 2016]
- If a person also has severe liver disease, for example, Child‑Pugh level B or C, work with a specialist multidisciplinary team with experience of managing TB and liver disease. [new 2016]
- Manage treatment with caution, ensuring careful monitoring of liver function, in:
- people with non‑severe liver disease
- people with abnormal liver function (including abnormal transaminase levels) before starting treatment for latent TB infection
- people who misuse alcohol or drugs. [new 2016]
- Ensure people having treatment for latent TB who also have social risk factors, such as misusing alcohol or drugs or being homeless, are linked to support services. They should also have an assessment of social needs and stability, including potential barriers to adherence or treatment completion. [new 2016]
- People in the groups listed in recommendation 1.2.4.1 who do not have treatment for latent TB, as specified in recommendations 1.2.4.2 to 1.2.4.8, for any reason should be advised of the risks and symptoms of TB (on the basis of an individual risk assessment), usually in a standard letter of the type referred to as 'Inform and advise' information (see section 1.1.2). [new 2016]
5. Managing latent TB in adults
- For adults between the ages of 35 and 65 years, offer drug treatments only if hepatotoxicity is not a concern. [new 2016]
- Offer testing for HIV before starting treatment for latent TB. See NICE guidelines on increasing the uptake of HIV testing among black Africans in England and increasing the uptake of HIV testing among men who have sex with men. [new 2016]
- Offer adults testing for hepatitis B and C before starting treatment for latent TB. See NICE guidelines on hepatitis B and C: ways to promote and offer testing to people at increased risk of infection and hepatitis B (chronic): diagnosis and management of chronic hepatitis B in children, young people and adults. [new 2016]
6. Managing latent TB in children and young people
- Consider testing children and young people for hepatitis B and C before starting treatment for latent TB. See NICE guidelines on hepatitis B and C: ways to promote and offer testing to people at increased risk of infection and hepatitis B (chronic): diagnosis and management of chronic hepatitis B in children, young people and adults. [new 2016]
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