Guidelines

Many countries have developed guidelines which incorporate the use of interferon gamma release assays (IGRA) such as T-SPOT.TB. The information below is provided as an abbreviated guide to these guidelines. However, we recommend you read the guidelines appropriate for your country.

UK

On 24 March 2011, The National Institute for Health and Clinical Excellence (NICE) published their new clinical Guidelines for TB control in England and Wales. They are available online at http://guidance.nice.org.uk/CG117/Guidance/pdf/English and are titled ‘Tuberculosis: clinical diagnosis and management of tuberculosis, and measures for its prevention and control’.

In recognition of the mounting clinical evidence in favour of IGRA technology, the new guidelines recommend going straight to an IGRA test in a number of specified indications including:

  • In an outbreak situation when large numbers of individuals may need to be screened
  • Recent arrivals from high incidence countries who are from 16 to 34 years old (older subjects may also be screened depending on the risk/benefits of treatment
  • The immunocompromised and some HIV subjects
  • New NHS employees who have recently arrived from high incidence countries or who have had contact with patients in a setting where TB is highly prevalent
  • Hard to reach populations

In addition, the new guidelines recommend that an IGRA test be considered for initial use in individuals for whom Mantoux testing may be less reliable, such as those who have been BCG vaccinated, and for use in individuals whose Mantoux test result is positive.

If your laboratory is in the UK and is not yet able to provide a blood test, then send your samples to Oxford Diagnostic Laboratories National TB Testing Services.

Germany

In May 2011 new Guidelines were issued. (Neue Empfehlungen für die Umgebungsuntersuchungen bei Tuberkulose. Diel R et al. Pneumologie 2011; DOI: 10.1055/s-0030-1256439.

They recommend that the routine use of a TST be replaced by an IGRA for contact tracing in the following cases and situations:

  • Adults from 15 years of age
  • Where there is a high probability of a false-negative TST in immunosuppressed patients such as HIV infected persons, haemodialysis patients or for patients prior to treatment with  anti-TNF-α inhibitors (as previously recommended)
  • BCG vaccinated subjects or in cases of a positive TST in the past (as previously recommended)

Switzerland

In November 2005 the Swiss Lung Association released recommendations for the diagnosis of TB infection in contact investigations using blood tests in Bulletin 45/10 of the Office Federal de la Sante Publique. The main points are:

  • Confirm a positive Mantoux tests with an IGRA
  • Use only an IGRA in immunocompromised subjects
  • Children are excluded from being tested with IGRA

In December 2007 the following guidelines were released for the use of IGRA to screen patients prior to administration of anti-TNF alpha therapies.

  • All patients should be screened for LTBI before being given anti-TNF alpha therapies
  • Screening should be based on history, chest x-ray and IGRA (TST is no longer recommended)
  • Preventive treatment should be given where LTBI is suspected as a result of:
    •  Positive IGRA
    •  Abnormal x-ray suggesting TB which was not adequately treated
    •  History of significant prior exposure

USA

The CDC produced IGRA guidelines in June 2010. The main points are as follows:

  • An IGRA may be used in place of (but not in addition to) a TST in all situations in which CDC recommends tuberculin skin testing as an aid in diagnosing M. tuberculosis infection
  • An IGRA is preferred for testing persons from groups that historically have low rates of returning to have TSTs read
  • An IGRA is preferred for testing persons who have received BCG (as a vaccine or for cancer therapy)
  • An IGRA or a TST may be used to test recent contacts of persons with active tuberculosis
  • An IGRA or a TST may be used for periodic screening of persons who might have occupational exposure to M. tuberculosis (e.g., health-care workers)

Japan

Guidelines for LTBI were released in 2013:

  • Test all dialysis patients with an IGRA
  • Test all transplant patients with an IGRA prior to transplantation
  • In pre-TNF alpha screening take patient history then carry out chest X-ray and if there is if no sign of active TB test with an IGRA
  • In new entrants from high incidence countries carry out a chest X-ray, and if there are signs of past TB test with an IGRA

Italy

Recommendations for the identification of LTBI were released jointly by the Associazione di Microbiologia Clinica Italiana (AMCLI) and the Federazione Italiana per le Malattie Polmonari Sociali e la Tubercolosi (FIMPST) in May 2006. The main points are:

  • Mantoux testing should be carried out and where positive an IGRA should be performed
  • In subjects with an expected TST positivity rate of 40% or more, and in immunosuppressed patients an IGRA should be carried out without a prior TST
  •  IGRA may be used along with other tests in the diagnosis of active disease

Netherlands

Dutch guidelines for contact tracing and screening were released in February 2008. The main points are:

  • Carry out a Mantoux test and where the subsequant induration is more than 5mm perform an IGRA.
  •  In subjects where the Mantoux “may be less reliable” perform an IGRA without a prior Mantoux.
  • IGRA can be used in place of a Mantoux in the work up for active disease diagnosis

France

In July 2011 the Haute Autorite de Sante updated guidelines concerning the use of IGRAs tests. It recommend the use of IGRAs tests in the following situations:

  • In contact tracing in subject 15 years or older
  • In children from the age of 5 years
  • In subjects more than 80 years old
  • In all patients infected with HIV
  • In patients before treatment with anti-TNF alpha
  • In healthcare workers
  • In immigrants children aged 5 to 15 years

If your laboratory is in France and is not yet able to provide a blood test, then send your samples to T-SPOT.TB Service.

Ireland

Draft guidelines published in July 2008 proposed that IGRA can be used in the following settings:

  • Contact tracing (in conjunction with a TST)
  • In certain circumstances IGRA, if available can be considered as the sole test for LTBI:
    • Where the TST may be falsely negative due to immunosuppression
    • When screening large numbers of individuals as part of a public health investigation
  •  Pre-employment screening of healthcare workers
  • For individuals, commencing immunosuppressive therapy e.g. TNF-α antagonists