Process
A microscopic amount of an allergen is introduced to a patient's skin by various means:
- Prick test or scratch test: pricking the skin with a needle or pin containing a small amount of the allergen.
- Patch test: applying a patch to the skin, where the patch contains the allergen
If an immuno-response is seen in the form of a rash, urticaria (hives), or (worse) anaphylaxis it can be concluded that the patient has a hypersensitivity (or allergy) to that allergen. Further testing can be done to identify the particular allergen.
The "scratch test" as it's called, is still very commonly used as an allergen test. A similar test involving injecting the allergen is also used, but is not quite as common due to increased likelihood of infection and general ineffectiveness by comparison. There are other methods available to test for allergy.
Some allergies are identified in a few minutes but others may take several days. In all cases where the test is positive, the skin will become raised, red and appear itchy. The results are recorded- larger wheals indicating that the subject is more sensitive to that particular allergen. A negative test does not mean that the subject is not allergic; simply that either the right concentration was not used or the body failed to elicit a response.
Read more about this topic: Skin Allergy Test
Famous quotes containing the word process:
“My advice to people today is as follows: If you take the game of life seriously, if you take your nervous system seriously, if you take your sense organs seriously, if you take the energy process seriously, you must turn on, tune in, and drop out.”
—Timothy Leary (b. 1920)
“We are in the process of creating what deserves to be called the idiot culture. Not an idiot sub-culture, which every society has bubbling beneath the surface and which can provide harmless fun; but the culture itself. For the first time, the weird and the stupid and the coarse are becoming our cultural norm, even our cultural ideal.”
—Carl Bernstein (b. 1944)
“At last a vision has been vouchsafed to us of our life as a whole. We see the bad with the good.... With this vision we approach new affairs. Our duty is to cleanse, to reconsider, to restore, to correct the evil without impairing the good, to purify and humanize every process of our common life, without weakening or sentimentalizing it.”
—Woodrow Wilson (1856–1924)