TB Skin Testing
TB skin tests are often performed regularly to detect Tuberculosis infection. We perform tb skin testing for people who may need it done for school, work, externships, immigration, travelers, foster parenting, etc. Our medical staff is especially trained on the correct administration, interpretation of results, and required documentation to provide for your TB skin test. We follow the Centers for Disease Control (CDC) guidelines for tb skin testing.
TB skin testing is also known as a PPD or a Mantoux test. PPD stands for purified protein derivative. A health care professional injects a small amount of fluid under the skin of the forearm. We check the area for a reaction in 48-72 hours.
We also offer the Quantiferon test. Quantiferon (QFT) is a blood test to detect TB. Quantiferon tests are also considered interferon gamma release assays (IGRAs).
TB Skin testing can be performed easily and quickly in our office. We offer appointments to minimize wait time. We also offer on-site testing for employers and schools for the TB test administration and reading of results.
TB skin testing may also be performed at a visit with other services. We provide services that you may additionally need for school, work, immigration, or otherwise such as:
What is a PPD or TB Skin test injection?
The purified protein derivative is a cell-free purified protein fraction that is obtained from a human strain of Mycobacterium tuberculosis grown synthetically and inactivated. It is a clear liquid. The injection is a very small amount, only 0.1 mL. The reason the results are read in 48-72 hours is because that is when the reaction is at its peak from the immune response.
The test can be done either once or twice: One Step or Two Step.
One Step: The tb skin test is administered once and the results are read in 48-72 hours
Two Step: The tb skin test is administered and the results are read in 48-72 hours. At least one week later, the tb skin test is administered again and the results are read in 48-72 hours.
What is the purpose of a tb skin test?
The purpose is to detect people who have been exposed to Tuberculosis and who are at risk for developing active disease. The majority of people in the USA who have a positive tb skin test reaction does not necessarily mean you have the active tuberculosis disease. It commonly means you may have latent infection or prior infection of the Tuberculosis bacterium.
How much does it cost?
What is Tuberculosis?
Tuberculosis is a disease caused by the bacteria Mycobacterium tuberculosis. It is spread through airborne droplets usually when a person with the disease coughs, speaks, sneezes, etc. and then someone inhales the droplet. The majority of the time, the infection affects the lungs, although it can sometimes affect other parts of the body. TB can be treated and cured with medication which is often prescribed to be takin for several months. TB is still a concern as well because the medications used to treat TB are not effective against some strains that are developing drug-resistance
Tuberculosis is still a leading cause of death worldwide, although on the decline in the USA. TB can be fatal if not treated in an infected person. That is why it is important to detect Tuberculosis in people who have been infected but are not yet ill.
Active TB: This is the active state of the infection and when the person is sick. It is also called TB disease. This can occur with initial infection or if latent infection is not fully treated and later reactivates. Symptoms often include:
- Fever (most common symptoms)
- Weight loss
- Night sweats
Latent TB: This state of the disease is dormant TB infection. The person is not yet contagious and does not have any symptoms. This is the ideal time to treat and prevent the person from developing active TB.
What is the purpose of a “Two Step” TB skin test?
People often ask, “Why do I need to have the test done again if my first result was normal?” Some settings such as in health care or other employments may require two tests following the Occupational Safety and Health Administration (OSHA) requirements and CDC guidelines because in some people the initial tb skin test result is falsely negative because the immune system’s response to TB has weakened over time. Performing a second test may allow more time for the immune system to react if the person was previously exposed to tb.
Healthcare workers and employees in places such as prisons or nursing homes often need an initial “two-step” tb skin test as a baseline and in the future only one test at regular intervals.
What is the difference between the Quantiferon tb blood test and the tb skin test?
|TB Skin Test||Quantiferon Blood Test|
What should I do if I test positive to TB?
A chest x-ray is often the next step in a person who has a positive tb skin test or Quantiferon. The chest x-ray often can be either normal, show suggestions of prior tb, or can show active disease. Even if the results are normal, you should inform your Primary Care Provider that you had a positive test so he/she can evaluate if further testing or treatment is indicated (such as in latent tb infection).