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Why can allergy counts change when the test changes?

Ask people whether they have a food allergy, test for sensitization, or require a clinical food challenge, and the resulting counts need not match. European studies show why the method of identifying cases belongs beside any prevalence headline.

5–7 min

Questions you could explore

  • Which differences between two surveys could look like a change in allergy rates?
  • How does a positive allergy test differ from a person's report of symptoms after exposure?

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