Tuberculosis is an infectious disease of the respiratory system caused by Mycobacterium tuberculosis infection, and blood tests for tuberculosis are auxiliary tests, not confirmatory. Tuberculosis blood test mainly depends on the following indicators: 1. Blood sedimentation, also called erythrocyte sedimentation rate, can reflect whether a patient with tuberculosis is acutely infected, that is, whether active tuberculosis is possible. The increased sedimentation rate indicates activity, but the specificity of the sedimentation index is poor. 2. Anti-tuberculosis antibodies react to whether or not the patient has been infected with tuberculosis, and most infections with tuberculosis are positive, but the index cannot distinguish between previous infections and acute infections. 3. A positive result indicates the presence of tuberculosis infection, with relatively high specificity and sensitivity. Therefore, among the above three blood tests, the results of the T-cell spot test for tuberculosis infection are more reliable, but the diagnosis of tuberculosis must be combined with medical history and symptoms to make a comprehensive judgment.