Reagent strip for semiquantitative total and specific IgE measurement: a comparison to radioisotopic methods

Determination of total and specific IgE using reactive test strips may afford a useful screening method in the in vitro diagnosis of allergens owing to easy use and possible correlation with established methods. T.D. LETI reactive strips for the semiquantitative determination of total IgE is a method combining classical fundamentals (sandwich anti-IgE-IgE-labeled anti-IgE) and the use of strip methods. It also permits determination of specific IgE levels in a wide range of Mediterranean and food (10) allergens. In a preliminary assessment, this method was correlated with isotopic PRIST for total IgE and with Phadebas RAST for specific IgE. The most important features are: a) no additional equipment besides serum or whole blood; b) cheaper and faster than PRIST for total IgE; c) correlation coefficient of 0.88 in the proposed range (n = 20) and 0.91 (n = 25) in the 10-500 U/ml range for PRIST/T.D. LETI for total IgE; d) specific IgE determination strips present sensitivity and specificity of 88 and 91%, respectively, in 180 allergens assayed in relation to Phadebas RAST. In conclusion, the in vitro diagnosis of allergens using reactive strips is currently a practical and simple method. By optimizing the top of the scale for total IgE and reducing the volume and/or time in specific IgE, it may prove to be an important screening method.