Department of Kinesiology

Effective August 1, 2006, all athletic training students must present proof of negative tuberculosis (TB) skin testing on an annual basis.  The testing verification must be presented prior to beginning any formal clinical rotation experiences.  Prior to testing at a local health unit, physician’s office, or LSU Student Health Center, you will be provided several “pre-testing” questions that will determine if you have any contraindication(s) to receiving the test (e.g., specific allergies, prior testing, etc.).  The cost for this test is approximately $5.00, and consists of a series of two visits within a 3 day period:  day 1 the test is administered and then return by no later than day 3 to have the skin test evaluated and documentation provided to you as proof of a negative test or additional testing.

The following information has been reproduced by the Centers for Disease Control (www.cdc.gov):

What is tuberculosis?
Tuberculosis (TB) is a disease that usually affects the lungs. TB sometimes affects other parts of the body, such as the brain, the kidneys, or the spine. TB disease can cause death if untreated.

How is TB spread?
TB germs are spread from person to person through the air. TB germs are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, laughs, or sings. TB is NOT spread by sharing silverware or cups, sharing cigarettes, or sharing saliva when kissing someone.

What are the symptoms of TB?
People with TB disease often feel weak or sick, lose weight, have fever, and have night sweats. If their TB disease is in the lungs, they may also cough and have chest pain, and they might cough up blood. Other symptoms depend on what part of the body is affected.

What is the difference between TB disease and TB infection?
People with TB disease are sick from the large number of TB germs that are active in their body. They usually have one or more of the symptoms of TB disease. These people may pass the TB germs to others. TB disease can cause permanent body damage and death. Medicines which can cure TB disease are given to these people.

People with TB infection also have the germs that cause TB in their body. But they are not sick because there are not as many of the germs, and the germs lie dormant (sleeping) in their body. They cannot spread the germs to others. However, these people could develop TB disease in the future, especially if they are in one of the high-risk groups listed under "Who gets TB disease?" People with TB infection can take medicine to prevent them from developing TB disease.

Who gets TB disease?
Once a person has TB infection, he or she has a higher chance of getting TB disease if the person

• Has HIV infection
• Has been recently infected with TB germs (in the last 2 years)
• Has other health problems, like diabetes, that make it hard for the body to fight germs
• Uses alcohol or injects illegal drugs
• Was not treated correctly for TB infection in the past

How can I tell if I have TB?
Get a TB skin test or the QuantiFERON®-TB Gold (QFT) blood test. If you have a positive reaction to either of the tests, you will probably be given other tests to see if you have TB infection or TB disease.

Where can I get a TB skin test or QFT? 
You can get a TB skin test from your doctor or local health department. You may be able to get the QFT at your local health department.

How are the TB tests given?
For a TB skin test, a health care worker uses a small needle to put some testing material, called tuberculin, just under your skin. This is usually done on the lower inside part of your arm. After you get the test, you must return in 2 to 3 days to see if there is a reaction to the test. If there is a reaction, the size of the reaction is measured.  If your health department does offer the QFT, some of your blood is taken for the test. You will be instructed on how to get the results of your test.

What if the test is negative?
A negative skin test usually means you are not infected. However, the test may be falsely negative if you were infected recently. It usually takes 2 to 10 weeks after exposure to a person with TB disease for your skin test to react as positive. The test may also be falsely negative if your immune system is not working properly.  A negative QFT usually means you are not infected.

What if the test is positive?
A positive skin test or QFT usually means that you have been infected with the TB germ. It does not necessarily mean that you have TB disease. Other tests, such as an x-ray or sputum sample, are needed to see if you have TB disease.

What if I had the BCG vaccine?
BCG is a vaccine for TB. This vaccine is not widely used in the United States, but it is often given to infants and small children in other countries where TB is common. The BCG vaccine does not usually protect adults against TB. You may still get TB infection or TB disease. Even if you have had the BCG vaccine, you will need a TB skin test or QFT to see if you may have TB infection or TB disease.

What should I do if I have TB infection or TB disease?
Get the required follow-up tests. Follow your doctor’s advice and take the medicine as prescribed. Today, both TB infection and TB disease can be treated and cured with medication.

Tuberculin Skin Testing
Last Updated: April 2006
U.S. Centers for Disease Control (www.cdc.gov)

What Is It?

The Mantoux tuberculin skin test (TST) is the standard method of determining whether a person is infected with Mycobacterium tuberculosis. Reliable administration and reading of the TST requires standardization of procedures, training, supervision, and practice.

How Is the TST Administered?
The TST is performed by injecting 0.1 ml of tuberculin purified protein derivative (PPD) into the inner surface of the forearm. The injection should be made with a tuberculin syringe, with the needle bevel facing upward. The TST is an intradermal injection. When placed correctly, the injection should produce a pale elevation of the skin (a wheal) 6 to 10 mm in diameter.

How Is the TST Read?
The skin test reaction should be read between 48 and 72 hours after administration. A patient who does not return within 72 hours will need to be rescheduled for another skin test.
The reaction should be measured in millimeters of the induration (palpable, raised, hardened area or swelling). The reader should not measure erythema (redness). The diameter of the indurated area should be measured across the forearm (perpendicular to the long axis).

How Are TST Reactions Interpreted?
Skin test interpretation depends on two factors:

• Measurement in millimeters of the induration
• Person’s risk of being infected with TB and of progression to disease if infected

Classification of the Tuberculin Skin Test Reaction

What Are False-Positive Reactions?
Some persons may react to the TST even though they are not infected with M. tuberculosis. The causes of these false-positive reactions may include, but are not limited to, the following:

• Infection with nontuberculosis mycobacteria
• Previous BCG vaccination Incorrect method of TST administration
• Incorrect interpretation of reaction
• Incorrect bottle of antigen used

What Are False-Negative Reactions?
Some persons may not react to the TST even though they are infected with M. tuberculosis. The reasons for these false-negative reactions may include, but are not limited to, the following:

• Cutaneous anergy (anergy is the inability to react to skin tests because of a weakened immune system)
• Recent TB infection (within 8-10 weeks of exposure)
• Very old TB infection (many years)
  
• Very young age (less than 6 months old)
  
• Recent live-virus vaccination (e.g., measles and smallpox)
  
• Overwhelming TB disease
  
• Some viral illnesses (e.g., measles and chicken pox)
  
• Incorrect method of TST administration
• Incorrect interpretation of reaction
  

Who Can Receive a TST?
Most persons can receive a TST. TST is contraindicated only for persons who have had a severe reaction (e.g., necrosis, blistering, anaphylactic shock, or ulcerations) to a previous TST. It is not contraindicated for any other persons, including infants, children, pregnant women, persons who are HIV-infected, or persons who have been vaccinated with BCG. \

How Often Can TSTs Be Repeated?
In general, there is no risk associated with repeated tuberculin skin test placements. If a person does not return within 48-72 hours for a tuberculin skin test reading, a second test can be placed as soon as possible. There is no contraindication to repeating the TST, unless a previous TST was associated with a severe reaction.

What Is a Boosted Reaction?
In some persons who are infected with M. tuberculosis, the ability to react to tuberculin may wane over time. When given a TST years after infection, these persons may have a false-negative reaction. However, the TST may stimulate the immune system, causing a positive, or boosted reaction to subsequent tests. Giving a second TST after an initial negative TST reaction is called two-step testing.

Why Is Two-Step Testing Conducted?
Two-step testing is useful for the initial skin testing of adults who are going to be retested periodically, such as health care workers or nursing home residents. This two-step approach can reduce the likelihood that a boosted reaction to a subsequent TST will be misinterpreted as a recent infection.

Can TSTs Be Given To Persons Receiving Vaccinations?
Vaccination with live viruses may interfere with TST reactions. For persons scheduled to receive a TST, testing should be done as follows:

• Either on the same day as vaccination with live-virus vaccine or 4-6 weeks after the administration of the live-virus vaccine
  
• At least one month after smallpox vaccination