Dr. MJ Bazos MD,
Meaning of a Positive Test
Tuberculosis (say: "too-burr-cue-low-sis") also
called TB, is an infection caused by a bacteria (a germ). Tuberculosis usually
affects the lungs, but it can spread to the kidneys, bones, spine, brain and
other parts of the body.
What does it mean if I have a
The most commonly used skin test to check for
tuberculosis is the PPD. If you have a positive PPD, it means you have been
exposed to a person who has tuberculosis and you are now infected with the
bacteria that causes the disease.
Do I have tuberculosis if I have a
positive PPD test?
Not necessarily. A person can be infected with
the bacteria that causes tuberculosis and not have tuberculosis disease. Many
people are infected with the bacteria that causes tuberculosis, but only a few
of these people (about 10%) go on to develop the disease. People who have
the disease are said to have "active" tuberculosis.
Healthy people who get infected with the
tuberculosis bacteria are able to fight off the infection and do not get
tuberculosis disease. The bacteria is dormant (inactive) in their lungs. If the
body is not able to fight off the infection and the bacteria continues to grow,
active tuberculosis develops.
Would I know if I developed active
You might not know that you have active
tuberculosis. Tuberculosis bacteria can grow in your body without making you
feel sick. However, most people with active tuberculosis don't feel well. People
with tuberculosis often feel tired and have a cough that won't go away. They may
also lose weight, or have a fever, or break out in a sweat in bed (called "night
sweats"). They may have trouble breathing.
If you have active tuberculosis, you will have
to get regular checkups and chest x-rays for the rest of your life to make sure
you stay free of disease, even after you have taken tuberculosis medicine.
Does a positive test mean that I can
give tuberculosis to someone else?
Not necessarily. After you have a positive PPD
skin test, you must have a chest x-ray and a physical exam to make sure that you
don't have active disease and that you're not contagious (able to spread the
It usually takes only a few days to tell whether
you're contagious. Most people with a positive skin test aren't contagious.
What will I have to do if my test is
To be sure that you remain healthy, your doctor
may recommend that you take medicine for 6 months to kill the tuberculosis
infection. If you don't take the medicine, the bacteria will remain in your
lungs, and you will always be in danger of getting active tuberculosis. The
medicine used to treat tuberculosis infection is isoniazid (say:
"eye-so-nye-ah-zid"), which is also called INH. You need to take 1 pill every
day for 6 months.
People who take INH may have side effects, but
not very often. Side effects include a skin rash, an upset stomach or liver
disease. Ask your doctor about other side effects that might happen.
What if I forget to take my
It is very important that you take the
medicine every day. Keep the medicine in a place where you will always see it.
Take it at the same time every day. Ask your doctor what to do if you forget to
take a pill.
Do I need to do anything else?
Every month you will need to visit your doctor
to get another prescription of the medicine you are taking and to be sure you
don't have any side effects or problems from the medicine. If you are feeling
well, your doctor will give you a prescription for the next month. It is
important that you stop drinking alcohol while taking INH. Drinking alcohol
while taking the medicine increases your risk of liver damage.
Could I still get active
tuberculosis after I take the medicine for 6 months?
Even after you take the medicine every day for 6
months there is a small chance that you could develop active tuberculosis
disease, because some bacteria are resistant to the medicine. Staying healthy
depends on having sensible living habits. You need enough sleep and exercise and
a healthy diet to keep up your health and resistance to the tuberculosis