Diagnostic evaluation of inhalant allergies: a cost-effectiveness analysis

The purpose of this study was to compare the cost-effectiveness of modified quantitative testing (MQT), intradermal dilutional testing (IDT), and in vitro allergy testing as diagnostic methods used in the management of patients with suspected IgE-mediated inhalant allergies.

A systematic review was conducted to determine key statistics for analysis, such as prevalence of disease, and sensitivity and specificity of each diagnostic modality. Costs were calculated based on charges from distribution companies to providers. A deterministic cost-effectiveness analysis then was conducted using a decision tree model to evaluate the various diagnostic strategies. After identifying results at baseline, we performed a sensitivity and threshold analysis to assess the strength of recommendations.

At an allergic rhinitis prevalence of 20%, MQT dominated IDT and in vitro testing, with 85 people correctly diagnosed at a baseline total cost of $6630 for the 100 patients tested. Although in vitro testing had the highest effectiveness, it had an incremental cost-effectiveness ratio of $3185. The results were sensitive to changes in the prevalence, costs, and sensitivities and specificities of the different modalities.

The prevalence of allergic rhinitis is high and rising according to many studies, leading to a growing population of patients requiring allergy testing. Not only does today's medical community want effective health interventions, but also there is pressure to make health care cost efficient. This study looks at the cost-effectiveness of various diagnostic allergy tests. In our model, we found MQT to be the most cost-effective method of diagnosing allergic disease.