If you have been exposed to someone who has tuberculosis, you will need to be checked by your physician to be certain that you have not been infected. Tuberculosis is transmitted by people who are actively sick with the disease when they cough, sneeze, sing, laugh or speak. The disease is not contagious until it has entered the active phase of the illness, so unless someone is visibly sick with TB, he is unlikely to be capable of transmitting the illness.
Call your Doctor
As soon as you become aware of having been exposed to TB, call your physician. He will probably ask you to come into the office for testing. Do not be concerned about the possibility of spreading the disease to others around you, as TB is only infectious in people who have had the illness for some time and have developed active symptoms, including a persistent cough, wheezing and hoarseness or gravelly speech.
Ask your doctor to perform a TB skin test. If she chooses to use this type of test, she will insert a small needle with tuberculin under your skin, which will create a tiny blister. You will need to return to the doctor's office in two or three days so that she can examine the blister to look for signs of irritation or rash. If none of these are present, then you should not have contracted TB from your exposure.
Your doctor may decide to perform a blood test to check for the presence of TB antibodies. He will draw blood and then send it out to a laboratory for testing, which may take up to two weeks before your results are available.
If your skin or blood TB test is positive, your doctor may wish to perform a chest x-ray to determine if you have developed active TB illness. Although TB infection is not contagious in and of itself, when the disease is active, it is highly contagious. Your doctor will look for characteristic lesions when examining your lung x-ray to determine if your infection has developed into an active (and contagious) illness. If the x-ray suggests that your disease is active, she will ask you about others with whom you may have had recent contact, as they will need to be checked for TB as well.
If your doctor has reason to suspect that you may have tuberculosis (a positive TB test or x-ray), he may ask you to collect a sample of your sputum, which is phlegm coughed up from your lungs. After the sample is sent away to a lab, a technician will examine a smear of sputum under a microscope on a slide to find evidence of TB bacteria. The sputum test can also help your doctor decide the proper type of antibiotic needed to treat your TB, depending on the type of bacterium present in the smear. The sputum test may take weeks to complete, as the bacteria for TB cultures grow rather slowly. Once diagnosed, however, your doctor can prescribe an appropriate antibiotic (one that the particular type of bacterium has not developed a resistance to).