The TB skin test is performed by injecting a small amount of testing liquid into the skin of the forearm. The test needs to be read 48 to 72 hours later by someone trained in reading skin tests. If it's positive then a chest x-ray is done to rule out active disease. If the chest x-ray is normal then the person is likely to have TB infection. Once a skin test is positive it will most likely stay positive and should not be repeated.
Tuberculosis kills more people today than any other infectious disease.
About 3 million people a year die from TB worldwide. However, death from TB is rare in the United States. King County averages about 116 cases of people with active TB per year and of these people the cure rate is almost one hundred percent. The Seattle-King County Tuberculosis Clinic's mission is to protect the residents of Seattle and King County from tuberculosis. Given that one third of the world's population have latent TB infection and three million people a year die of TB, the disease remains a serious public health threat.