The significance of serum total immunoglobulin E for in vitro diagnosis of allergic rhinitis.

BACKGROUND

Allergic rhinitis is diagnosed by clinical parameters with no widely accepted screening test. Measurement of total serum immunoglobulin E (IgE) has limited use in the general population due to a low negative predictive value. The value of total IgE level in select populations undergoing in vitro allergy testing remains unknown. The aim of this study is to determine the utility of total serum IgE in the in vitro diagnosis of allergic rhinitis.

METHODS

A retrospective chart review of patients undergoing testing for allergic rhinitis was performed. Clinical parameters, total IgE level, and enzyme-linked immunosorbent assay (ELISA) for serum-specific IgE levels were analyzed with multivariate logistic regression. The positive and negative predictive values and a receiver operating characteristic (ROC) curve were used to assess the utility of total IgE in predicting serum-specific IgE test results.

RESULTS

Records from 1073 patients were reviewed. ROC curve for total IgE >150 IU/mL (Σ 0.88) indicates good discrimination in identifying patients with sensitization by in vitro testing, whereas low total IgE level had strong negative predictive value (0.87, IgE <10) in identifying negative specific IgE testing. Multivariate logistic regression showed that differences in covariables did not significantly change the odds of a positive in vitro allergy test panel.

CONCLUSION

Serum total IgE level is useful in the in vitro diagnosis of allergic rhinitis. In vitro testing for specific IgE may be unnecessary in patients with low serum total IgE, whereas high total IgE level suggests that in vitro testing would confirm specific sensitizations in patients with allergic rhinitis.