Questions and Answers About TB
Return to Table of Contents
How can I get tested for
TB?
What if I have been vaccinated
with BCG?
If I have latent TB infection,
how can I keep from developing TB disease?
What if I have HIV infection?
How can I get tested for TB?
A TB skin test is the only way to find out if you have
latent TB infection. You can get a skin test at the health department
or at your doctor's office. You should get tested for TB if:
- you have spent time with a person with known or suspected to
have TB disease
- you have HIV infection or another condition that puts you at
high risk for TB disease
- you think you might have TB disease
- you are from a country where TB disease is very common (most
countries in Latin America and the Caribbean, Africa, Asia, Eastern
Europe, and Russia)
- you inject drugs
- you live somewhere in the U.S. where TB disease is more common
(homeless shelters, migrant farm camps, prisons and jails, and
some nursing homes)
A health care worker can give you the TB skin test. The health
care worker will inject a small amount of testing fluid (called
tuberculin) just under the skin on the lower part of your arm.
After 2 or 3 days, the health care worker will measure your reaction
to the test. You may have a small bump where the tuberculin was
injected. The health care worker will measure this bump and tell
you if your reaction to the test is positive or negative. A positive
reaction usually means that you have latent TB infection.
If you have a positive reaction to the skin test, your doctor or
nurse may do other tests to see if you have TB disease. These tests
usually include a chest x-ray and a test of the phlegm you cough
up. Because the TB bacteria may be found somewhere besides your
lungs, your doctor or nurse may check your blood or urine, or do
other tests. If you have TB disease, you will need to take
medicine to cure the disease.
If you have recently spent time with someone with infectious TB,
your skin test reaction may not be positive yet. You may need a
second skin test 10 to 12 weeks after the last time you spent time
with the infectious person. This is because it can take several
weeks after infection for your immune system to be able to react
to the TB skin test. If your reaction to the second test is negative,
you probably do not have latent TB infection.
Return to Top of Page
What if I have been vaccinated with
BCG?
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. BCG vaccine does not always protect people from
TB.
If you were vaccinated with BCG, you may have a positive reaction
to a TB skin test. This reaction may be due to the BCG vaccine itself
or to latent TB infection. But your positive reaction probably means
that you have latent TB infection if:
- you recently spent time with a person who has TB disease
- you are from an area of the world where TB disease is very common
(most countries in Latin America and the Caribbean, Africa, Asia,
Eastern Europe, and Russia)
- you spend time where TB is common (homeless shelters, drug-treatment
centers, health care clinics, jails, prisons)
Return to Top of Page
If I have TB infection, how can I keep
from developing TB disease?
Many people who have latent TB infection never develop
TB disease. But some people who have latent TB infection are more
likely to develop TB disease than others. These people are at high
risk for TB disease. They include:
- people with HIV infection
- people who became infected with TB bacteria in the last 2 years
- babies and young children
- people who inject drugs
- people who are sick with other diseases that weaken
the immune system
- elderly people
- people who were not treated correctly for TB in the past
If you have latent TB infection (a positive skin test reaction)
and you are in one of these high-risk groups, you need to take medicine
to keep from developing TB disease. This is called treatment for
latent TB infection. There are many treatment options. You and your
health care provider must decide which treatment is best for you.
The medicine usually used for the treatment of latent TB infection
is a drug called isoniazid or INH. INH kills the TB bacteria that
are in the body. If you take your medicine as prescribed, treatment
for latent TB infection will keep you from ever developing TB disease.
Most people must take INH for at least 6 to 9 months. Children
and people with HIV infection may need to take INH for a longer
time.
Sometimes people are given treatment for latent TB infection even
if their skin test reaction is not positive. This is often done
with infants, children, and HIV-infected people who have recently
spent time with someone with infectious TB disease. This is because
they are at very high risk of developing serious TB disease soon
after they become infected with TB bacteria.
It is important that you take all the pills prescribed for you
so that your treatment for latent TB infection is effective. If
you start taking INH, you will need to see your doctor or nurse
on a regular schedule. He or she will check on how you are doing.
Very few people have serious side effects to INH. However, if you
have any of the following side effects, call your doctor or nurse
right away:
- no appetite
- nausea
- vomiting
- yellowish skin or eyes
- fever for 3 or more days
- abdominal pain
- tingling in the fingers and toes
Warning: Drinking alcoholic beverages (wine, beer, and
liquor) while taking INH can be dangerous. Check with your doctor
or nurse for more information.
People who have latent TB infection but do not receive treatment
for latent TB infection need to know the symptoms of TB. If they
develop symptoms of TB disease later on, they should see a doctor
right away.
Return to Top of Page
What if I have HIV infection?
A person can have latent TB infection for years without
any signs of disease. But if that person's immune system gets weak,
the infection can quickly turn into TB disease. Also, if a person
who has a weak immune system spends time with someone with infectious
TB, he or she may become infected with TB bacteria and quickly develop
TB disease.
Because HIV infection weakens the immune system, people with latent
TB infection and HIV infection are at very high risk of developing
TB disease. All HIV-infected people should be given a TB skin test
to find out if they have latent TB infection. If they have latent
TB infection, they need treatment for latent TB infection as
soon as possible to prevent them from developing TB disease.
If they have TB disease, they must take medicine to cure the disease.
TB disease can be prevented and cured, even in people with HIV
infection.
Return to Top of Page
|