June 6, 2013

Multidrug-Resistant Tuberculosis (MDR-TB) Increasing

By Julie Suchanek, MBA, MT (ASCP)
Metropolitan Medical Laboratory

Identifying TB Infection is Essential

Tuberculosis is a deadly lung disease. It continues to be a significant threat to humanity. One-third of the world’s population is currently infected with TB. In 2011, nearly NINE BILLION people worldwide became ill with TB, according to the Centers for Disease Control and Prevention (CDC).

Not everyone who becomes infected develops active TB disease, however. Individuals who are infected with Mycobacterium tuberculosis and who show no symptoms (such as persistent coughing, slight fever, fatigue, loss of appetite and weight, night sweats, and more) are said to have “latent TB infection” (LTBI). Perhaps 5-10 percent of people with latent TB infection will progress to active TB, according to the Centers for Disease Control (CDC). Latent TB was the most commonly diagnosed infection among migrants globally, and was found in nearly half of those travelling to the U.S., according to a report last December from the CDC.

Even though the actual number of TB cases in the U.S. is low, the rates of multidrug-resistant TB (MDR-TB) are at epidemic proportions in countries such as India, China, and Eastern Europe. Extensively drug-resistant TB (XDR-TB) is an especially dangerous strain that is resistant not only to the two most potent TB drugs, but also a handful of second-line drugs. XDR-TB is presently rare in the U.S.

Can I get TB?

Anyone can get TB. You can get TB if you breathe in TB bacteria from an infected person coughing or sneezing. Casual contact doesn’t necessarily lead to infection – it depends on how much time is spent in close contact with an infected
person who is coughing. In addition, certain communities are at higher risk of TB infection:

• healthcare workers
• the elderly
• immigrants
• military personnel
• homeless individuals
• inmates
• people taking certain medications that suppress the immune system
• people with a weakened immune system

If you’re exposed to TB, the organism can attack any part of your body, but it most commonly invades your lungs. You can become infected and have no symptoms initially, or you may have a mild cough and a slight fever.


A simple blood test (such as Quantiferon TB Gold) can now be performed, which is more specific than the tuberculin skin test (TST). With this new blood test, there are fewer false positives than with the TST, resulting in fewer chest x-rays and physical exams for people who don’t need them. Also, only one patient visit is required.


Drugs offer the most effective therapy for TB, although an increasing number of TB organisms have become resistant to drugs commonly used in treatment.

Metropolitan Medical Laboratory, PLC is one of the largest accredited laboratories in the states of Illinois and Iowa, and has provided this community with quality laboratory services for 99 years. Visit www.metromedlab.com. Tell your doctor, “I want my lab tests to go to Metro.”