Tuberculosis is an infectious disease, usually in the lungs, that is spread from person to person through the air. This can happen when people cough, sneeze, laugh or sing. TB can also affect other parts of the body, but much less often. It is possible to have TB and have few if any symptoms because it can lie dormant in the body for years before being activated.

Please visit the "Questions and Answers about TB" page of the Center for Disease Control and Prevention Web site for extensive information about TB.


The Spread of TB

Usually, TB is spread to others who are in close contact regularly over a period of time, such as: family members, roommates, coworkers, and friends. The best way to stay healthy is to have a test to check for TB once a year.


About the TB Test

The current method to test for exposure to TB is called the Mantoux test (PPD). The Mantoux test consists of injecting a very small amount (0.1ml) of an inactivated form of the germ just under the skin. You then return to the clinic to have the test read in 48-72 hours (or 2-3 days). A nurse will examine the site of injection for a reaction. If there is no redness or swelling (and you are not immunocompromised) the test is read as negative. If there is a swelling at the site larger than 10mm, it may mean that the test is positive and will require further evaluation.


Potential Indications for the 2-Step Tuberculin Skin Test (TST)

TB 2-Step testing is recommended by the Centers for Disease Control (CDC) as a baseline test for health care workers and other selected populations who have the possibility of exposure to tuberculosis as part of their student or work experience. TB 2-Step testing is done in order to get an accurate baseline TB test prior to contact with the public or patients that could have active TB.

If a person has had previous unknown infection with tuberculosis and it has been more than a year since their last TB test, it is possible for their TB test to read negative even though they have been infected. This is due to the waning of the antibody response after infection. However, receiving the TB test will stimulate the antibodies and another test done shortly within a week or the first test will demonstrate the TB infection by being read as positive or reactive.


What is the 4 visit 2-Step Tuberculin Skin Test(TST)?

  • (Visit 1) The 1st TEST is placed. You must return in 48-72 hours (2-3 days) for the test to be read. 
  • (Visit 2) The 1st TEST is read. If the test is negative, return to clinic in 1 -2 weeks for the second test placement.
  • (Visit 3) The 2nd TEST is placed. Return in 48-72 hours for the second TEST to be read.
  • (Visit 4) The 2nd TEST is read.


Positive Reactions to a PPD and its Implications

If you have a positive PPD it does not mean that you have Tuberculosis. A positive PPD means that your body's immune system recognizes the TB protein injected into your arm and is mounting an antibody response. This is why you have a raised red area at the site of injection. This reaction shows that you have been exposed to the germ that causes Tuberculosis. The exposure may be recent or may have occurred years ago. A positive test may, but does not indicate the presence of active Tuberculosis disease. Therefore, once you have had a positive skin test, you should thereafter receive a chest X-ray, or health clearance to demonstrate no active Tuberculosis.

Some people immunized in countries with a high incidence of TB were given the BCG vaccine and may test positive as a result. However, even with a history of BCG vaccination, a positive test is still a positive test.

DO NOT HAVE ANY MORE SKIN TESTS AFTER YOU HAVE TESTED POSITIVE (>10-15mm). Whether you have an active disease or not, you will always test positive.


TB Skin Test Fee

All TB skin tests are currently Free of Charge.


SRJC staff and faculty may utilize Student Health Services clinical services to obtain their required work related tuberculosis clearance, at no cost to the employee. Clinical Staff members will need PPD placements in accordance with hospital facility guidance. Academic staff members who do not work in medical facilities are screened at hire and every 4 years. Recent changes in Ed Code allows for a Risk Assessment process. Results of the Risk Assessment determine whether a PPD test is needed. Completed Risk Assessments are forwarded to Human Resources for documentation.


For additional information, please contact Cindy Dickinson at