Tuberculosis Skin Testing

(TB Disease, Consumption, Phthisis)

TB, or tuberculosis, is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria can attack any part of your body, but they usually attack the lungs. TB is spread through the air from one person to another. The bacteria are expelled into the air when a person with TB disease of the lungs or throat coughs or sneezes. People nearby may breathe in these bacteria and become infected.

People who become infected with TB bacteria usually have had very close day-to-day contact with someone who has TB disease (e.g. a family member, friend, or close co-worker). You’re not likely to get infected from someone who is coughing in line at a supermarket or sitting near you at a restaurant. Dishes do not spread TB, nor do drinking glasses, sheets or clothing. In most people who become infected, the body is able to fight the bacteria to stop them from growing. The bacteria become inactive, but they remain alive in the body and can become active later. This is called latent TB infection (LTBI). People with latent TB infection:

  • Have no symptoms
  • Don’t feel sick
  • Can’t spread TB disease to others
  • Usually have a positive skin test reaction
  • Can develop TB disease later in life if they do not receive treatment for LTBI.

Many people who have latent TB infection never develop TB disease. In these people, the TB bacteria remain inactive for a lifetime without causing disease. But in other people, especially people who have weak immune systems, the bacteria become active and cause TB disease. People with LTBI can take medicine so that they will never develop TB disease.

TB bacteria become active if the immune system can’t stop them from growing. The active bacteria begin to multiply in the body and cause TB disease. Some people develop TB disease soon after becoming infected, before their immune system can fight off the TB bacteria. Other people may get sick later, when their immune system becomes weak for some reason. Babies and young children, people infected with HIV, people with chronic disease and the elderly may have weakened immune systems. Other people can also have weak immune systems, especially people with any of these conditions:

  • Substance abuse
  • Diabetes mellitus
  • Silicosis
  • Cancer of the head or neck
  • Leukemia or Hodgkin’s disease
  • Severe kidney disease
  • Low body weight
  • Certain medical treatments (such as corticosteroid treatment or organ transplants).

The Food and Drug Administration (FDA) has determined that tuberculosis (TB) disease is a potential adverse reaction from treatment with the tumor necrosis factor-alpha (TNF-α) antagonists infliximab (Remicade®), etanercept (Enbrel®), and adalimumab (Humira®).
[Source: Centers for Disease Control and Prevention. “Tuberculosis Associated with Blocking Agents Against Tumor Necrosis Factor-Alpha — California, 2002 – 2003.” MMWR August 5, 2004 / 53(30);683-686, (4/05)]

Symptoms of TB depend on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs. TB in the lungs may cause:

  • A bad cough that lasts longer than 2 weeks
  • Pain in the chest
  • Coughing up blood or sputum (phlegm from deep inside the lungs)

Other symptoms of TB disease are:

  • Weakness or fatigue
  • Weight loss
  • No appetite
  • Chills
  • Fever
  • Sweating at night

People with TB disease can be treated and cured if they seek prompt medical help. Please contact your health care provider, local health department or the Missouri Department of Health and Senior Services (866-628-9891) if you have other questions about latent TB infection or TB disease.

We provide testing Monday-Wednesday. You must return 48 hours after the test is given to have the results read. For more information call (417) 466-2201. Go to our fees section for current charges.