SUMMARYThe thin layer rapid use epicutaneous test (TRUE‐test) is a new patch test, in which the allergens are incorporated in a thin, flexible solid vehicle on a water impermeable backing. The vehicle shows good stability for allergens, which are crystallized, micronized or emulsified into a gel. The TRUE‐test produces an exact dosage, even surface spread and high bioavailability for the allergens. This solves the problems of low bioavailability, uncertain dosage and uneven surface distribution which are commonly seen when petrolatum is used as the vehi