The TB test is a skin test in which a tiny amount of purified protein derived from the TB germ is injected into the skin to see if your body recognizes the protein and produces a local inflammation at the skin site. The testing is safe and relatively painless. It is not possible to become TB infected by testing.
As it takes some time for this kind of reaction to take place, the test is "read" 48 to 72 hours after it is placed. For example, if your skin test is placed at 10:30 AM on Monday, you will need to return to have it read after 10:30 AM on Wednesday, but no later than 10:30 AM on Thursday.
A skin test with a reaction is read by measuring the area of induration (swelling) at the site. A test is positive for TB if the induration is greater than certain millimeter parameters when risk factors such as ones immune status and potential exposure history are taken into account.
Testing for Tuberculosis (TB) is available on a walk in basis at the Public Health and Human Services clinic, 1005 West Worley. We offer testing on Monday, Tuesday, Wednesday, and Friday from 8 a.m. to 4:30 p.m..
After the initial testing, you must return to the clinic to have the test site examined two to three days later (48 to 72 hours). A fee will be requested, unless the test is done because the person has been in contact with an active case. Such "contact investigation" tests are free.
A positive TB skin test as determined by the nurse when you come back to have the test "read," means that at some time in the past you were around someone with "active" TB and have acquired a TB infection.
Positive skin tests are quite common in the United States. Randomly tested, about 1 in 100 Americans would have a positive TB skin test.
How did I get this? At some time in your life you must have been around someone who had "active" Tuberculosis. This could have been a coworker, fellow passenger on a public conveyance, family member, etc. Data indicates that usually you must "share" the air of someone with TB for at least 8 hours to acquire the infection. The TB germ is breathed into the lungs as part of tiny droplets which float in the air after someone with "active" TB coughs or laughs. You then become infected and your skin test is evidence that your immune system has fought the TB germs that you have.
Can I give this to others? Once attacked by your body's defenses the TB germs usually become dormant (go to sleep), and you cannot pass the germs to someone else. Later, if your immune system has been weakened either by severe or chronic illness, HIV, drug or alcohol abuse, or old age, the dormant TB can "wake up" and cause Tuberculosis disease and symptoms.
Only someone with active TB disease is infectious (can pass the disease to someone else). A chest x-ray is needed to determine if the TB is active or dormant.
The Chest X-Ray: The nurse who reads your test can write a prescription for your chest x-ray which can usually be done the same day, locally. If you are insured or of sufficient income, you will need to pay for the chest x-ray yourself. Otherwise a social worker at the Health Department can discuss other payment options.
At the time of the skin test reading an appointment will be made with the TB Nurse to follow up on the chest x-ray results and discuss treatment options.
Before 1950, Tuberculosis was difficult to treat and there was a stigma of danger and fear attached to it. With the use of new effective antibiotics, the number of TB cases plummeted, and public awareness of TB as a problem has faded. Memories of earlier times are hard to erase, so if you test positive for TB, you may experience some personal fear in yourself and from others.
Rest assured, however, that TB is curable and that the treatment of TB infection does not usually involve separation from society as in times past.
What will the nurse discuss with me following a positive skin test? The chest x-ray will indicate whether you have "active" disease or, as is usually the case, dormant TB infection. You and the nurse will discuss the option of beginning TB therapy, signs and symptoms of TB, as well as lifestyle issues such as exercise, diet, and drug or alcohol use which may affect your health with or without treatment. All those having positive TB skin tests will be encouraged to have an HIV test
What is the difference in treatment between active TB or dormant TB? If active TB disease is evidenced on the chest x-ray, then treatment of the disease is mandated by law to protect the public from the spread of TB. Treatment usually involves taking at least 3 pills every day for 2 months followed by 2 pills a day for another 7 months. Sputum specimens may be ordered and the treatment adjusted by your doctor depending on the results
Active cases are treated with "Directly Observed Therapy" (DOT) and depending on the medicines ordered, the patient will receive their medicine daily (or 2-3 times a week) from the TB nurses to assure that no doses are missed.
it is important for the person with active TB to follow the direction of the TB nurses regarding the use of masks and isolation from the general public to prevent the spread of TB until such time it is proven that the medicine has worked to make them noninfectious
If a dormant TB Infection is indicated by a normal chest x-ray, treatment is voluntary and usually involves taking 2 pills (an antibiotic and a vitamin) for 9 months. Once started, the series needs to be completed to prevent the formation of antibiotic-resistant TB.
It is important to note, that tuberculosis treatment requires a commitment of time and a determination to complete the drug series. The full treatment of TB infection will kill the dormant germs and prevent the development of active TB later in life.
The medicines used to treat TB are strong and can sometimes affect the liver of those taking TB therapy, especially if they are over the age of 35 or have a history of alcohol abuse.
What happens if we decide to start the treatment? The Health Department will provide all tests and all medications prescribed to treat TB free of charge.
Your physician or the Health Department's physician will order the medicine and you will be given a one-month supply of medication, and must return to the clinic once a month to pick up the next month's pills. This procedure allows the nurse an opportunity to make sure that the pills are not adversely affecting you.
Future Testing: Once you have had a positive skin test, you will always have a positive test, whether you proceed with the treatment or not. If, in the future, you have symptoms of TB, you will need a chest x-ray to rule out an active TB disease. On completion of therapy you will receive a letter explaining this, which you can use to show to future employers, schools, etc., should you be required to get a TB test
To learn more about tuberculosis, please visit our external website directory.