Step 5. Establish specific allergic sensitisation: skin prick tests; specific RAST (if available); specific bronchial challenge (if exposure not on Schedule, or association doubtful).

• Immunological tests: skin prick tests and serological tests (RAST) for sensitivity and specificity, cross reactivity;
• List of RAST tests available;

• Specific bronchial challenge testing (that is the gold standard!):

  • > 20% fall in FEV₁ significant;
  • disadvantages: risk to patient; reproducing appropriate exposure; inaccessibility of specialist centres.