Can we manage demand for allergy testing by restricting requests to a small number of prime target allergens?

Demand for expensive tests such as allergen-specific IgE is expanding far faster than for cheaper tests: at Burton Hospital the annual growth rate is 24%. Different hospitals have different policies on allergen testing. We report a comparison of the effect of requesting policy on diagnostic yield.

All results from five years of allergen testing were downloaded from the data warehouse at Burton, and a representative sample of recent results was evaluated from Ipswich Hospital. Statistical analysis by chi(2) test and significance tests for differences of proportions were carried out.

Ipswich hospital used a standard four-allergen panel for respiratory patients and demonstrated a statistically significantly lower positivity rate for three of those four allergens. No relationship between the number of allergens tested and the probability of a positive result was shown - the probability of a positive result was approximately 0.3. Number of allergen-specific IgE tests requested/patient have remained roughly constant over 5(1/2) years but total demand has increased.

Selective requesting for allergen-specific IgE testing may be more effective than use of a standard panel but this cannot be conclusively proven. It is not appropriate to attempt to limit workload by specifying a maximum number of tests that are allowed for any individual patient.