Tuberculosis is a disease caused by a germ called mycobacterium tuberculosis that is spread from person to person through the air. Latent Tb lives but does not grow in the body and is not contagious. Where as, Active TB grows in the body and is very contagious. They both have similarities when it comes to symptoms. Such as, chest pain, weight loss, loss of appetite, coughing of sputum, etc. Only test can diagnose whether or not a person has Latent or Active TB. Doctors take x-rays, sputum stain, sputum cultures and skin and blood test to figure out the diagnose.