Tuberculosis (TB) remains one of the most common infectious diseases worldwide. It is caused by the bacterium Mycobacterium tuberculosis . It most commonly affects the lungs (pulmonary TB), but it can also involve other organs (extra-pulmonary TB), such as the brain, lymph nodes, bones, kidneys, intestines, uterus, and other organs. Although several laboratory and radiological tests are available today, diagnosing TB is not always straightforward. Many patients become confused when one TB test is positive while another is negative. They often wonder, "Which report is correct?" Each TB test looks for a different aspect of the disease. Some detect the bacteria directly, while others detect the body's immune response. Therefore, discrepancies are expected in certain situations. Understanding the strengths and limitations of each test helps prevent unnecessary anxiety and inappropriate treatment. Not every mycobacterium causes tuberculosis. True tuberculosis is caused by memb...