Consolidated Guidelines

A systematic review of studies reporting the outcomes of interest, including local reactions – that is, injection site reactions (ISR) and systemic adverse events from TBSTs – was undertaken. The following databases were searched for studies from inception until 30 July 2021: Medline, Embase, e-library, the Chinese Biomedical Literature Database and the China National Knowledge Infrastructure Database. The test manufacturers were contacted for individual studies, and studies were identified through a public call for data by WHO.

Diagnostic accuracy studies evaluating sensitivity, specificity and concordance (agreement) of TBSTs were identified. There were no identified studies on the efficacy of TPT based on diagnostic test results, on the predictive value for progression to TB disease or on the proportion started on TPT.

In 2021, WHO commissioned a systematic review of published and unpublished data on the new class of tests for TB infection not previously reviewed by WHO.

The overarching policy question was:

Should Mtb antigen-based skin tests (TBSTs) for TB infection be used as an alternative to the tuberculin skin testtests (TST) or WHO-endorsed interferon-y release assays (IGRA) to identify individuals most at risk of progression from TB infection to TB disease?

The following tests were included in the evaluation:

1.2.1. Justification

Tuberculosis (TB) infection is a state that is characterized by persistent immune response to stimulation by Mycobacterium tuberculosis (Mtb) antigens with no evidence of clinically manifest TB disease (1). It is estimated that about a quarter of the world’s population is infected with Mtb. Testing for TB infection can identify individuals who would benefit the most from TB preventive treatment (TPT). However, there is no gold-standard test to diagnose TB infection.

Tuberculosis (TB) infection is a state that is characterized by persistent immune response to stimulation by Mycobacterium tuberculosis (Mtb) antigens with no evidence of clinically manifest TB disease.¹ It is estimated that about a quarter of the world’s population is infected with Mtb. Testing for TB infection increases the probability that individuals who are the target for TB preventive treatment (TPT) will benefit from such treatment. However, there is no gold-standard test to diagnose TB infection.

The recommendations included in these consolidated policy guidelines on tuberculosis (TB) are the result of a collaborative effort among professionals from a range of specialities. The World Health Organization (WHO) is grateful for their time and support.

TB antigen-based skin tests (TBSTs) for the diagnosis of TB infection

GDG meeting on use of TBSTs for the diagnosis of TB infection, Geneva, Switzerland, 31 January–3 February 2022

Guideline Development Group