New guidelines for screening for tuberculosis and latent tuberculosis infection pre-immunosuppressive therapy in the Netherlands: a targeted and stratified approach

A considerable proportion of the world’s population is latently infected with Mycobacterium tuberculosis (MTB) complex (LTBI) but in low-incidence counties as the Netherlands (4.6 TB cases/100.000 /year) LTBI prevalence is predominantly found among the elder population and foreign-born residents. In resource-rich countries implementation of immunosuppressive therapies with “biologicals”, show a rapid rise with increased risk of LTBI progressing to, often serious forms of, active TB. Worldwide it is advised to screen all candidates for of immunosuppressive therapies for TB with a chest X-ray and LTBI with at least one test [interferon gamma release assays (IGRAs) and/or tuberculin skin tests (TSTs)]. Screening requires an acceptable balance between over-diagnosis and under-diagnosis, also because the tests are not perfect and can be false-negative and false-positive in populations almost without exposure. We developed a guideline advising a stratified pre-immunosuppression screening policy, using a questionnaire classifying candidates in three screening strategies, based upon their age, country of birth, documented TB contacts and tests in the past and other risk factors, such as profession and travel history. A very low risk group can start with immune therapy immediately and a very high risk group should receive preventive treatment for LTBI, both without the need for further testing. A medium risk group should be tested by TST and IGRA and receive preventive treatment if at least one test is positive. Since the questionnaire is not yet validated monitoring of this approach on a national level is needed to evaluate the performance of this stratified screening strategy, based upon risk analysis.