Skin tests

Skin tests are used to monitor specific cell-mediated immunity, or late hypersensitivity reactions. We can use them to determine the success of the patient's immunization after vaccination or to support the diagnosis of a past or an ongoing infection. Tests are performed in vivo by applying the antigen into the pacient´s skin, usually in the forearm.

Test examples
The most used skin tests include, for example, the tuberculin test, the Ducrey test and the Shick test, the lepromin test, the Brucellin test or the Frei test.

Tuberculin test
Tuberculin test (Mantoux test) is mostly used to determine the effectiveness of vaccination against tuberculosis  in children. As of November 1 2010, dthe nationwide compulsory vaccination of newborns against tuberculosis was revoked in the Czech Republic, which is why the test is now being used increasingly to diagnose ongoing infections. A mixture of proteins produced by mycobacteria (tuberculin) was once used for the application, today a PPD (purified protein derivative) is used. The dose causes an inflammatory reaction with redness and hardening at the injection site.
 * The diameter of the lesion is measured after 48–72 hours and it is evaluated:
 * less than 5 mm – negative,
 * between 6 mm and 10 mm – postvaccination allergy,
 * more than 15 mm – postinfection allergy,
 * between 10 mm and 15 mm – can be both types of allergies.

Ducrey test
Ducrey test consists of administering a suspension of inactivated hemophiles. A positive result means the pacient had a Haemophilus ducreyi infection.

Schick test
Schick test is used to demonstrate antitoxic immunity against Corynebacterium diphtheriae. After the intradermal administration, no reaction is seen in immune subjects; redness at the injection site (erythematous reaction) occurs in non-immune subjects.

Lepromin test
Lepromin test (Mitsuda test) is used to diagnose Leprosy. The antigen (lepromin) is obtained from lesions.

Brucellin test
Brucellin test uses inactivated brucellas or brucelin or brucelergen as an antigen. The result is not very valuable in areas with brucellosis and in suspected inapparent infections.

Frei test
Frei test is used to diagnose lymphogranuloma venereum or to detect a Chlamydia trachomatis infection.

Related articles

 * Chancroid
 * Cultivation
 * Serology
 * Tuberculosis (pathology)