Clinical application of interferon gamma release assays for diagnosis of latent tuberculosis infection in children / 临床儿科杂志

ABSTRACT

Latent tuberculosis infection (LTBI) is defined as a patient is infected with Mycobacterium tuberculosis, without signs and symptoms or radiographic evidence of tuberculosis (TB). Until recently, the only test to identify latent tuberculosis infection was the tuberculin skin test (TST). But in BCG-vaceinated or non-mycobacterium tuberculosis infected individuals TST may be false positive and some babies or immunocompromised individuals have negative results on TST even they were proved to be with TB disease. So it is in need of a new method with higher sensitivity and specificity to diagnose LTBi. More recently, a new diagnostic method of interferon gamma release assays (IGRA) was paid close attention, and in some countries it replaced TST and became the final diagnostic method of LTBI. IGRA has high specificity for Mycobacterium tuberculosis without being influenced by BCG vaccinated or non-mycobacterium tuberculosis infection. In people with normal immune systems, the sensitivity of IGRA is same as TST for TB disease, and in immunocompromised individuals the sensitivity of IGRA is higher than TST. IGRA will have important application in diagnosis of LTBI although it cannot absolutely take the place of TST.