Question of the Week

March 20, 2006


Have you ever had a skin test to check for Tuberculosis? Did you ever wonder why?

"The tuberculin skin test is used to determine if a person has TB infection. A substance, called tuberculin, is injected into the skin. Tuberculin is purified protein and not a vaccine or contains any germ cells. The immune system of most people who have TB infection recognizes tuberculin and this will cause a reaction in the skin."

And if the test shows that a person does have a TB infection, what does that mean?

"Tuberculosis (often called TB) is an infectious disease that usually attacks the lungs, but can attack almost any part of the body. Tuberculosis is spread from person to person through the air. ... It is important to understand that there is a difference between being infected with TB and having TB disease. Someone who is infected with TB has the TB germs, or bacteria, in their body. The body's defenses are protecting them from the germs and they are not sick. Someone with TB disease is sick and can spread the disease to other people. A person with TB disease needs to see a doctor as soon as possible."

TB is an international health issue.

"[Friday, March 17, 2006] Although the current tuberculosis treatment strategy has helped cure nearly 20 million patients of TB, the incidence of TB continues to climb. March 24 is World TB Day, and to observe the occasion, this week's issue of The Lancet medical journal has a special TB focus. TB remains the leading cause of death from a curable infectious disease, Dr. Christopher Dye, from the World Health Organization in Geneva notes."

"Is TB a problem in the United States? In the United States, TB has re-emerged as a serious public health problem. In 2001, based on provisional data reported to the U.S. Centers for Disease Control and Prevention, the number of cases has decreased for the ninth straight year to 15,991 cases of active TB (infection with full-blown disease symptoms). This all-time low is due largely to improved public health control measures. In addition to those with active TB, however, an estimated 10 to 15 million people in the United States are infected with M. tuberculosis without displaying symptoms (latent TB) and about one in ten of these individuals will develop active TB at some time in their lives. Minorities are affected disproportionately by TB: 54 percent of active TB cases in 1999 were among African-American and Hispanic people, with an additional 20 percent found in Asians."

"In the United States, TB has re-emerged as a serious public health problem," but TB is "a curable infectious disease."

"With appropriate antibiotic treatment, TB can be cured in more than nine out of ten patients. Successful treatment of TB depends on close cooperation between the patient and doctor and other health care workers. Treatment usually combines several different antibiotic drugs which are given for at least six months, sometimes for as long as 12 months. Patients must take their medicine on time every day for the 6 to 12 months. ... If patients don't take all their medicine the way their doctor tells them, they can become sick again and spread TB to their friends and family. Additionally, when patients do not take all the drugs the doctor has prescribed or skip times when they are supposed to take them, the TB bacteria learn to outwit the TB antibiotics, and soon those medications no longer work against the disease. If this happens, the person now has resistant TB infection."

Most cases of TB can be cured with the proper treatment -- especially if they are caught early.

"The Mantoux method of application is the preferred type of skin test because it is the most accurate. When the Mantoux skin test is performed, a needle is injected into the upper skin layer of the patient's arm. The arm is examined 48 to 72 hours after the tuberculin injection in order to evaluate the reaction on the patient's skin. Any swelling that can be felt around the site of the injection, also known as induration, is measured. The diagnosis of TB infection depends on the size of the measured induration and the patient's individual risk factors."

While a skin test is the preferred method of testing, it is not 100% accurate. If health care professionals suspect that a patient is infected with TB or has the TB disease, then other tests can be done to confirm the diagnosis.

"In December 2004, the FDA approved a new diagnostic test for M. tuberculosis-complex infection known as the Quantiferon®-TB Gold. This in vitro diagnostic test measures the amount of interferon-gamma produced by cells in whole blood that have been stimulated by mycobacterial peptides. ...

"If TB infection or disease is suspected, a chest x-ray should be taken. The chest x-ray helps the clinician determine any presence of TB or old healed TB disease. In TB infection, the chest x-ray is usually normal.

"A Bacteriological Examination ... is an examination of the secretions from the lungs (sputum), directly under a microscope or by culture."

Questions of the Week:
Why are some encouraged (and others required) to be tested for TB? Who should get a TB test? In your area, who is required by law to get tested for TB? How can people find out if they are at higher risk for having been infected with TB, or for having the TB disease. What do your peers and family members need to know about TB and TB testing? Is there anyone who does not need, or who should not have, a TB test? In what situations might different tests for TB be recommended for different people?

Please email me with any ideas or suggestions.
Note: Due to increasing amounts of SPAM sent to this account, please include "QOW" in the subject line when sending me email.

I look forward to reading what you have to say.

Health Community Coordinator
Access Excellence @ the National Health Museum

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