結核病的主要傳染途徑是經由空氣傳播，但並非感染結核菌之後都會發病。結核病又分開放性結核病與潛伏性結核病。開放性結核病臨床症狀，如咳嗽、發燒、胸痛等徵狀，配合檢驗結果可診斷開放性結核病。但潛伏性結核病感染者則無任何臨床徵狀，臨床不易診斷。針對是某些免疫功能缺陷或是免疫系統受到抑制的病人，若感染潛伏性結核病，因本身的免疫力下降而促使處於休眠狀態的結核菌活化，進而進展成再活動性肺結核病，造成結核病的傳播。因此，潛伏性結核病的診斷與治療對於控制結核病傳播是非常重要。在臨床上並沒有標準方法用於診斷潛伏性結核病，至目前結核菌素皮膚試驗和丙型干擾素釋放分析方法被應用在潛伏性結核病的篩檢。注射過卡介苗或感染非結核分枝桿菌會與結核菌素會產生交叉反應，容易產生偽陽性的分析結果。丙型干擾素釋放分析的原理是使用排除卡介苗結核菌株非結核分枝桿菌的特異性抗原進行檢測，多篇研究證實其靈敏度和特異性高於結核菌素皮膚試驗。本文將綜合比較診斷潛伏性結核病的方法，提供臨床醫護人員與檢驗人員之參考。

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis that spread through the air from person to person and mainly attacks the lungs. However, inhaling the bacilli dose not mean the host will develop an active tuberculous infection. It has two types of condition after infection: active tuberculosis and latent tuberculosis. Active form has symptoms and may spread bacilli to others. Latent tuberculosis infection (LTBI) is a state in which a person is infected with M. tuberculosis without any clinical symptoms. Some populations are at increased risk of reactivating latent tuberculosis infection and progressing to active tuberculosis because of immunosuppressive or immunodeficiency. Hence, to identify and treat LTBI is not only reduced the risk of development of active tuberculosis but also important for public TB control. However, there is no gold standard for diagnosis LTBI. There are two types of assay for screening latent tuberculosis infection, tuberculin skin test (TST, in vivo test) and interferon gamma release assay (IGRA, in vitro test). TST is the most widely used screening test for LTBI, yet it has frequently false positive results among BCG-vaccinated persons or caused by certain nontuberculous mycobacteria. IGRA contains tuberculosis specific-antigens, which are not present in BCG vaccine and most nontuberculous mycobacteria. Many reports showed that the sensitivity and specificity of IGRA is higher than TST. This article will review the diagnosis methods for latent tuberculosis infection.