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Mantoux Test

The Mantoux skin test is given using a needle and syringe to inject 0.1 ml of 5 tuberculin units of liquid tuberculin between the layers of the skin (intradermally), usually on the forearm (Figure 3.1). A tuberculin unit is a standard strength of tuberculin. The tuberculin used in the Mantoux skin test is also known as purified protein derivative, or PPD. For this reason, the tuberculin skin test is sometimes called a PPD skin test. With the Mantoux skin test, the patient's arm is examined 48 to 72 hours after the tuberculin is injected. Most people with TB infection have a positive reaction to the tuberculin. The reaction is an area of induration (swelling that can be felt) around the site of the injection. The diameter of the indurated area is measured across the forearm (Figure 3.2); erythema (redness) around the indurated area is not measured, because the presence of erythema does not indicate that a person has TB infection (Figure 3.3).

Source of images: Self Study Modules on Tuberculosis, Part 3, Diagnosis of Tuberculosis Infection and Disease. March 1995. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, Atlanta Georgia.

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