.

Also, what is an induration?

Medical Definition of induration 1 : an increase in the fibrous elements in tissue commonly associated with inflammation and marked by loss of elasticity and pliability : sclerosis. 2 : a hardened mass or formation.

Similarly, what is TB induration? "Reading" the skin test means detecting a raised, thickened local area of skin reaction, referred to as induration. Induration is the key item to detect, not redness or bruising. Read skin tests 48-72 hours after the injection when the size of the induration is maximal.

Similarly, how do you know if a TB skin test is positive?

TB Skin Testing Results If you have a raised, hard bump or there's swelling on your arm, you have a positive test. That means TB germs are in your body. But it doesn't always mean you have active tuberculosis disease. If you don't have a reaction, your test is negative.

How is induration measured?

The reaction should be measured in millimeters of induration (palpable, raised, hardened area or swelling).

1. Do not measure erythema (redness).
2. The indurated area should be measured across the forearm (perpendicular to the long axis).