Site: abdominal wall below ensiform process, or breast below nipple, or inner surface of forearm.
Application: rub in with the finger (using moderate pressure) a small particle of salve about the size of a pea.
Rub it in into an area about 5 cm.; rub 1 minute.
4. Reaction:
In 24 to 48 hours—either numerous small reddened spots which disappear in a few days, or numerous small nodules, or coalescing nodules on a red base, etc.
5. Interpretation of Reaction:
Positive reaction is assumed to indicate existing tuberculous infection somewhere in the body; does not indicate that the process is active.
6. Field of Application of Percutaneous Tuberculin Test:
The percutaneous tuberculin test fails in a large proportion of tuberculosis cases.
The test is used rarely at present.