Intradermal Injection of Tuberculin/Mantoux Test
For a correct reading of a Mantoux test (tuberculin skin test) it is important that the tuberculin solution is injected correctly.
If the tuberculin is injected too deeply, it may be necessary to repeat the test.
Be aware of
In order to detect a suspected infection with Mycobacterium tuberculosis, for example after travelling abroad, a test should be performed no sooner than 2-3 months after the infection may have occurred.
A sterile 1.0 ml disposable syringe with a short-bevelled 25 or 26-gauge needle should be used for administering the test.
Jet injectors or "multiple puncture" devices must not be used.
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Disinfection before the injection is not necessary
- If the injection site is disinfected anyways, the skin must be completely dry before the injection.
The injection should be given in the middle third part of the dorsal side of the forearm.
Stretch the skin between finger and thumb.
Hold the needle almost parallel to the skin.
Insert the needle-point with the bevelled side upwards so that the needle opening is visible.
The needle should be inserted about 2 mm and be visible under the epidermis.
In the picture, the skin is slightly lifted for better illustration
Inject the tuberculin slowly.
The appearance of a small wheal indicates tha the tuberculin has been given correctly intradermally. The wheal will disappear within approximately 10 minutes.
In the picture, the skin is slightly lifted for better illustration
The result may be read approximately 3 days after the injection.
Reading:
A flat and uneven induration surrounded by erythema.
An induration diameter of 6 mm or above is defined as a positive reaction.
Last revised 30 August 2010