Mantoux test
A tuberculin test is a skin test with tuberculin, a preparation that is filtered from liquid mycobacterial cultures. Tuberculin calls when applied to the skin produces a reaction with sensitized T - lymphocytes, which are formed in contact with tuberculosis bacteria. The test thus serves to recognize a previous or current tuberculosis infection. Tuberculin was developed by Robert Koch originally as a tuberculosis cure ( therapeutic ). It proved, however, to be unsuitable. As tuberculosis diagnostic contrast, it is been extremely important in the last 100 years ( see below).
Implementation
Pirquet test
An early test after the introduction of tuberculin was the Pirquet test. Clemens von Pirquet in 1907 was named after him tuberculin skin reaction. This tuberculin skin was applied to the degreased, and then incised in the skin ( scarified ). If arose after two to three days nodules ( papules ), the result was positive, a previous tuberculosis was assumed. The test is no longer used.
Stamp test
A simplified possibility of carrying consisted tuberculin with a commercially available punch ( Tinetest ®, Tubergen ® test ) applied to the inside of a forearm. There was punctiform visible. The test could be read between the fourth and seventh day after injection and was considered positive if a palpable papule had notice of at least 2 mm in diameter - a reddening alone was not sufficient. The disadvantage of this method was its relatively low specificity and sensitivity. The production of punch testing was therefore discontinued in 2005. The test is no longer available in Germany and its neighboring countries, as it has no authorization by the BfArM (or equivalent agencies in other countries ) more.
After intracutaneous Mantoux
For a more accurate study of the Mantoux test (international is the name Mantoux test more common ) in use. Here (epidermis) are 2 TU ( tuberculin units) tuberculin RT23 Statens Institut Copenhagen (licensed in Germany since September 2005) strictly intracutaneously into the top layer of skin injected. After injection, the test site must not rub or excessive UV radiation exposure. The test is better read after a minimum of 48 hours after 72 hours and is in healthy tuberculosis exposed as an indication of tuberculosis infection when an indurated swelling ( induration ) of more than 6 mm transverse diameter of the forearm shows. In immunocompromised disturbed contact persons and young children the suspected case is reached at an induration of 5 mm. For persons who are BCG vaccinated, the test only applies to an induration of more than 15 mm as infectious suspicious. The now available interferon - gamma tests may here contribute to more precise clarification of the question of tuberculosis infection. It is more reliable than the punch test, the more accurate administration of the Tuberkulinmenge.
The test proves one made by infection or vaccination. The activity of the disease can not display this test.
Assessment
A positive reaction can occur with the BCG vaccine not only upon or after tuberculosis, but also by other mycobacteria infections and tuberculosis after previous vaccination. In fresh tuberculosis or severe immune deficiency of the tuberculin test may be negative despite the existence of disease.
The conventional tuberculin test is still an important tool for diagnosis. Atypical environmental mycobacteria, however, occur increasingly taking the place of the decline in M. tuberculosis infections. Between these two pathogen types of tuberculin test does not differentiate because of cross-reactivity. New test method with highly specific TB antigen detection are therefore developed, please refer to γ - interferon test.
Swell
- Tuberculosis
- An immunochemical test method
- Microbiological test method