Video Link

No video available

Background/Purpose

Grass pollen is a major cause of respiratory allergy worldwide. Grasses are botanically classified in the family of Gramineae and in particular in the subfamily of Pooideae, which includes the species most commonly responsible of allergic sensitisation, such as Anthoxantum odoratum, Dactylis glomerata, Festuca elatior, Holcus lanatus, Lolium perenne, Phleum pratense, and Poa pratensis. Another species causing respiratory allergy is Cynodon dactylon, which belongs to the subfamily of Panicoideae. These species have variable importance in different geographical areas. In Europe, Dactylis glomerata, Poa pratensis, Lolium perenne and Anthoxantum odoratum are homogeneously distributed, while Phleum pratense is the dominant grass in Northern regions and in the United Kingdom, and Cynodon dactylon is present only in Southern regions [. To date, more than 150 allergens from 52 grass species are known, classified in 13 groups according to similar physicochemical and immunologic properties . Among these allergens, the molecules from Phleum pratense Phl p 1, Phl p 2, Phl p 5, and Phl 6, and their homologous in other grasses, are known as major allergens.

Procedure

The test area is cleaned and labeled using an appropriate skin marker. When multiple tests are being performed there should be a minimum of of 3cm between them. The skin is pricked lightly and quickly vertically through the sample allergen . A new micro lancet should be used for each substance being tested. The excess sample allergen should be removed immediately with an absorbent paper towel.
The wheals should be read after 15-20 minutes. For a positive reaction, the wheal should be >= 3mm in diameter. A valid result also requires a positive histamine reaction >=3mm and a negative saline control reaction of < 3mm.
Performed: Axially

Dialog

Subcutaneous test of grass allergen.

Criteria

• <3mm wheal
• No systemic reaction

Measurement

LOINC Code

Scale/Grading

selection range; grade - LOINC ID
Option - Value option selection range; grade - LOINC IDPass < 3 ; Pass - Equivocal = 3 ; Fail - Fail > 3 ; Fail -