Question

in a tuberculin test, a dilute extract of m. tuberculosis is

o injected into the skin
o swallowed by the patient
o inhaled into the lungs
o spread over the skin of the lower back

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Explanation:

The tuberculin test, also known as the Mantoux test, is a common method to check for tuberculosis (TB) infection. In this test, a small amount of tuberculin (a purified protein derivative from the bacteria Mycobacterium tuberculosis) is injected into the skin (usually on the forearm). The injection is done using a needle and is a form of intradermal injection. After 48 - 72 hours, the site of injection is examined for induration (hardening) and redness. The size of the induration helps in determining if the person has been infected with M. tuberculosis. Swallowing or inhaling the extract is not part of the standard tuberculin test procedure, and spreading it over the lower back skin is also not the correct method. The key is the intradermal injection route which is a standard medical procedure for this test.

Answer:

injected into the skin