$Unique_ID{BRK01668} $Pretitle{} $Title{Use of Different Methods for Tuberculosis Testing} $Subject{test skin tuberculosis Special Procedures Procedure Laboratory Lab Tests Test Skin Subcutaneous Tissue tissues Testing hypodermic syringe needle Tine tines old tuberculin OT purified protein derivative PPD antibodies bacteria tuberculin infectious antibody bacterial bacterium infection infections} $Volume{P-20, A-20} $Log{} Copyright (c) 1991-92,1993 Tribune Media Services, Inc. Use of Different Methods for Tuberculosis Testing ------------------------------------------------------------------------------ QUESTION: Several members of our family were tested recently for the possibility of tuberculosis. When we discussed this later, we found that different methods were being used and we wondered why. One type of test did not use a hypodermic needle, while the other did. Are both these tests recognized for testing for tuberculosis? Please clear up our confusion, if you can. ------------------------------------------------------------------------------ ANSWER: With the number of cases of tuberculosis on the upswing again, many more Americans will be undertaking similar procedures, so I suppose it is a fine idea to describe these tests to you in detail. The test that did not use a hypodermic syringe and needle is called the Tine Test. It is a button with several sharp points or "tines" that have been coated with either old tuberculin (OT) or purified protein derivative (PPD), both of which cable of causing a skin reaction in people who have antibodies to the tuberculosis bacteria. Since these antibodies are present only in people who have been exposed to the bacteria, the skin reaction is an important finding. The Tine test is the not as sensitive as the other test, for the amount of tuberculin that enters the skin can not be carefully controlled, and so the test is only used as a screening test. Since it is easy to perform and quickly accomplished it is just fine for this purpose, particularly in school populations among young people. However if the test is positive, the more accurate test, with precise amounts of PPD, must be used. This test, which uses a needle and syringe, is called the Mantoux Test. A precise amount of PPD, 0.1 mL, is injected under the skin in the area of the arm, usually between the wrist and the inner side of the elbow. The arm is inspected from 3 to 5 days later, and if a reddened, hardened area has developed, it is measured. The size of this "induration," from 5 to over 15 mm, can be significant, and may be interpreted as showing that the individual has been exposed to infectious tuberculosis. When the test is positive, other examinations, including chest x-rays, are indicated before treatment is started. ---------------- The material contained here is "FOR INFORMATION ONLY" and should not replace the counsel and advice of your personal physician. Promptly consulting your doctor is the best path to a quick and successful resolution of any medical problem.