The present invention provides an in vivo determination of the presence of Mtb infection in immunocompromised persons or those who are superinfected with HIV and stably assesses the presence of Mtb infections in individuals who are immunocompromised or who are superinfected with HIV. Disclosed is the use of a Mycobacterium tuberculosis antigen in the preparation of a diagnostic reagent for skin examination (skin examination reagent). [Selection] Figure 1本発明は、免疫不全者もしくはＨＩＶとの重感染者におけるＭｔｂ感染症の存在のｉｎ ｖｉｖｏ判定および免疫不全者もしくはＨＩＶとの重感染者である個人におけるＭｔｂ感染症の存在を安定的に評価するための皮膚検査の診断試薬（皮膚検査試薬）の調製へのＭｙｃｏｂａｃｔｅｒｉｕｍ ｔｕｂｅｒｃｕｌｏｓｉｓ抗原の使用を開示する。【選択図】図１
