Question

You are helping to give Mantoux tests to children who are being registered for kindergarten in your community. How should you administer this test?

a) Interdermal injection into the inner forearm
b) Intramuscular injection into the vastus lateralis
c) Subcutaneous injection into the umbilical area
d) Insert at a 45-degree angle into the deltoid

Answer 1

The Mantoux test is administered by an interdermal injection into the inner forearm to screen for TB exposure. It should be read after 48-72 hours, and further testing may be needed in areas where the BCG vaccine is common.

Step-by-step explanation:

The Mantoux test, also known as a tuberculin skin test, is used to determine if someone has been exposed to the bacterium that causes tuberculosis (TB). The correct way to administer this test is by an interdermal injection into the inner forearm. This is done by using a small needle to inject a purified protein derivative (tuberculin) just beneath the surface of the skin, creating a small bump (wheal). After 48-72 hours, the site is examined for a reaction, which may present as redness, swelling, or hardness known as an induration. A positive result doesn't necessarily mean there is an active infection; it indicates that the person's immune system has been exposed to TB before.

If the test is done in countries where the bacillus Calmette-Guérin (BCG) vaccine is commonly given, the interpretation can be complicated. A person vaccinated with BCG may have a positive skin test even if they are not infected with TB, as the vaccine can cause a response to the test. In such cases, additional tests, like a chest radiograph, may be necessary to confirm TB exposure.