• The skin test is the most common TB diagnostic method.injection image by DXfoto.com from Fotolia.com
  
  Tuberculosis is a potentially fatal infectious disease that affects the lungs. The infection can remain asymptomatic but in some cases will develop in to the fully active form of the disease. The symptoms of TB include coughing, bloody sputum, weight loss and fever. The disease is spread through the air when infected people cough or sneeze.
  
  

Skin Test

• The Mantoux skin test offers a simple method of diagnosing TB. A small amount of purified protein derivative tuberculin is injected just under the surface of the skin. The substance is purified to prevent development into TB, but it still causes a reaction in someone who carries TB. If the injection site becomes red and swollen with a hard red bump it is likely that the subject is carrying the infection. A health care professional will examine your reaction to the injection and determine a suitable course of action depending on the outcome. If the Mantoux test is positive, the doctor will order a blood test for confirmation.
  
  

Blood Test

• The blood test will be used to confirm or rule out TB infection in people who developed a hard red bump after their skin test. It is also used for people at higher risk of infection, such as those that have come in to contact with confirmed carriers of the infection and those displaying symptoms of the disease. The blood test produces results faster than the skin test. A blood sample is taken and exposed to the bacteria that causes TB. The blood's reaction to the agent is monitored and used to diagnose the disease.
  
  

Chest X-Ray

• After a positive TB test of either type, a doctor will normally order a chest X-Ray to establish the clinical affects of the disease and its stage of development. The X-Ray reveals how much of the lung surface area is infected with the disease and whether the disease is at the stage where nodules are being produced. White spots on the lung indicate that the immune system is protecting the body from the spread of the disease.
  
  

CT Scan

• The CT scan is very similar to the X-Ray in that it takes an image of the lungs for examination. It is the method by which the image is captured that differs, rather than the diagnostic process itself.
  
  

Culture Test

• Your doctor may order a culture test to determine the best method of treatment. By collecting either a sample of sputum or stomach acid, your doctor will expose the TB bacteria to a range of treatments to determine which one is most effective at treating the disease.