Table 2.

Results of Questionnaire Survey of Drug Intradermal Test (IDT) methods used in 20 European allergy centers.

Questions	Answers
Number of IDT done per year	30–6,000 IDT
Do you use dissolved and filtered drug solution for IDT?	Yes: 5/20 (crushed pills or other non-injectable forms of the drugs, diluted in saline then filtered) No: 15/20
Which solvent do you use?	Saline or phenolated saline: 16/20 Sterile distilled water or the solvent recommended as diluent for the infusion: 4/20
What volume do you inject?	No fixed volume but a volume to raise a wheal: 12/20A fixed volume: 0.02 ml: 1 0.03 ml: 3 0.04 ml: 3 0.05 ml: 1
Site of injection	Upper arm: 4 Forearm: 14 Back: 1 Non-specified: 1
Measurement of the Wi	Yes: 15/20 No: 5/20
What are your criteria for a positive immediate reading?	The existence of a given diameter of W20: 4 centers (3–5 mm depending on the centers) The existence of a given diameter of erythema at 20 min (E20) 3 mm ≥: 6 mm depending on the centers (2 centers also consider the W20). W20 ≥ Wi + 3 mm: 6 centers

Wi, mean diameter of the wheal (bleb or papule) immediately after ID injection.

W20, mean diameter of the wheal or the wheal developed at 20 min.

E20, mean diameter of the erythema developed at 20 min.