Cost-effective allergy screening: a retrospective observational study.

Summary: Background. Allergies represent a substantial health concern affecting individuals across all age groups. Diagnostic screenings, such as phadiatop and phadiatop infant, are employed to identify specific IgE antibodies associated with allergic reactions. This study delves into the relationship between total IgE levels and screening test outcomes, with the objective of establishing a total IgE threshold capable of predicting the likelihood of negative results in these screenings. Methods. This retrospective observational study included adults and children under 15 years old who underwent total IgE tests in addition to phadiatop and phadiatop infant screenings from January 2018 to December 2022. Exclusion criteria were applied to patients with insufficient serum samples or those whose IgE determinations or screening tests had been invalidated according to standard laboratory protocols. Results. Data analysis uncovered a robust correlation between total IgE levels and screening test outcomes. Additionally, thresholds of 20 UI/mL and 28 UI/mL were pinpointed for total IgE levels, below which the likelihood of obtaining a positive result in phadiatop or phadiatop infant, respectively, significantly decreased. Conclusions. These findings present cost-effective strategies for healthcare practitioners by recommending the initial use of total IgE testing. Subsequently, reflex testing with phadiatop or phadiatop infant, depending on the IgE value, could be considered.