Health Maintenance > PPD: Mantoux Tuberculin Skin Test

PPD: Mantoux Tuberculin Skin Test

1. What is the reason for having a PPD tuberculin (TB) skin test?
Tuberculosis screening (risk questionnaire) is usually done at age 1, and when a child enters a new school. The screening asks 4 questions:

  1. Has the child been in contact with someone known to have active TB?
  2. Has anyone living in the house (or the child) ever lived in, or was born in, a country where TB is common? (Countries in Africa, Asia (except Japan), the Caribbean, South America, etc.)
  3. Does the child come in almost-daily contact with an adult who is at high risk for TB? (nursing home or prison workers, drug abusers etc.)
  4. Does the child have AIDS, cancer, or other immune suppression?

If the answer is YES to any of these questions, then a PPD skin test is recommended.

The tuberculin skin test (PPD) can show if a person has been exposed to tuberculosis (TB) germs. These germs can cause you to feel sick with TB disease, or remain in your body and not make you feel sick. When the germ doesn’t cause you to feel sick, it’s called latent tuberculosis infection; you feel fine and you cannot spread the germ to others; but there is a risk that you will become more sick with TB over time. The PPD is a skin test, not an immunization.

2. How is the Mantoux test given?
A small amount of (killed) testing material (PPD) is injected just under the top layer of the skin of a person’s forearm, with a very small needle and syringe. The needle will feel like a pinprick. 2 to 3 days later, the skin test reaction is measured, and the results are recorded by a trained health care worker. Only a trained health care worker can determine if the reaction is negative or positive.

3. Should I be tested if I’ve been given a BCG vaccination?
Yes, if there is a reason for a PPD. A history of BCG vaccine does not affect the PPD reading. A positive PPD reading is followed by a blood test and chest XRay, regardless of a prior BCG vaccination.

4. Are there any side effects from the Mantoux PPD skin test?
Not usually. However, a person who has been exposed to TB germs may occasionally have a sizable reaction, which may cause some itching, swelling, or irritation. This should disappear in 1 to 2 weeks. Rarely, in highly sensitized persons, blistering or ulceration may occur. This should be brought to the attention of your health care provider for treatment. Allergic reactions are extremely rare.

5. If I have a positive PPD, will I need to be tested again?
You will probably not need another PPD. Once a skin test is positive, it may turn negative after a few years, but your status as “PPD positive” remains. You never have to have another TB test again, but you should keep documentation of the result to show to your health care providers. Generally, a positive PPD will be confirmed with an XRay and a blood test, which is expensive but more accurate.

6. How should I care for the PPD test site?

  • Bathe/shower as usual. Pat (do not rub) the arm dry after washing.
  • Don’t scratch, wipe, or scrub the arm. Do not cover with a Band-Aid.
  • Don’t apply creams or lotions. If it itches, put a cold compress on it.

** Remember that the PPD must be read in 2-3 days, or it must be repeated !! **