Done Mantoux Test For Child. No Weal Appeared. How Do I Know It Was Administered Correctly?

Posted on Tue, 4 Sep 2012

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Tue, 4 Sep 2012 Answered on

Mon, 24 Sep 2012 Last reviewed on

Question : How do I know if a Mantoux test was administered correctly? I took my five year old for testing today but I never saw the wheal appear. How soon will the wheal/blister usually disappear. If the test was done incorrectly, can I re do it, and how soon?

Answered by Dr. Pavan Kumar Gupta (30 minutes later)

Hello
Thanks for the query.
After a mantoux test, a person who has been exposed to the bacteria is expected to mount an immune response in the skin containing the bacterial proteins.
The reaction is read by measuring the diameter of induration across the forearm in millimeters. If there is no induration, the result should be recorded as "0 mm". Erythema (redness) should not be measured.
In your child case the test is negative as there is no induration on the injection site.
There is no chance of getting the test incorrectly done because injection has been given.
However you may repeat the test again after a gap of three weeks for your satisfaction.

I hope to have answered your query however you may revert to me for any further query.
Best of luck
Thanks

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar