Before ordering any allergy tests, including feedstuff tests, any administration of corticosteroids should be stopped. To do so, the following withdrawal times are recommended:
- local/topical corticosteroids: 2 – 4 weeks
- oral corticosteroids (e.g. Prednisolone): up to 8 weeks
- depot cortisone preparations (e.g. Voren®): up to 3 months
If these times cannot be observed, false negative results are possible. In the case of a positive result, the reaction class must be assessed taking into account the previous administration of cortisone.
Please note that other itch-suppressing medication may also have a negative impact on the allergy test. Our allergy team will be pleased to advise you.
Allergy tests should be performed during the season or at the end of the season and not earlier than one month after the onset of the symptoms, as the test may be false negative if performed out of season.
