ABSTRACT
BACKGROUND: In vitro serum allergen-specific IgE tests have been routinely used in the clinical diagnosis of allergic diseases. We evaluated the clinical usefulness of a newly introduced multiple antigen screen test, Advansure Allergy Screen (LG Life Science, Korea) (LG-Screen) for the detection of allergen specific IgE. METHODS: A total of 180 sera (80 for inhalant and 100 for food panels) were tested by LG-Screen and RIDA Allergy Screen (R-biopharm, Germany) (RIDA-Screen) assays. According to the 58-60 specific allergens or allergen groups, the positive rates and agreement rates were analyzed using the cut off levels of class 2. For the quantitation of total IgE and specific IgE, nephelometry and ImmunoCAP test were performed in the sera showing discrepant results between the two allergy screen assays. RESULTS: The agreement rate and kappa value (k) of total IgE between the two allergy screen assays was 73.9% and 0.333. LG-Screen showed higher agreement rate with nephelometry than RIDA-Screen. The positive rates to common outdoor inhalant and food allergens were significantly higher in RIDA-Screen. Overall agreement rate of specific IgE between the two allergy screen assays for 58 allergens was 86.7% (6,086/7,020) (k, 0.293). In samples showing discrepant results between the two allergy screen assays, concordance rate of allergy screen assay with ImmunoCAP assay was 70.9% (449/633) for LG-Screen (k, 0.585) and 29.1% (184/633) for RIDA-Screen (k, -0.303). CONCLUSIONS: LG-Screen showed a favorable agreement with RIDA-Screen and ImmunoCAP assays, and it could be used for the detection of allergen specific IgE in the clinical laboratory.
Subject(s)
Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Allergens , Hypersensitivity, Immediate/diagnosis , Immunoglobulin E/blood , Immunologic Tests/methods , Reagent Kits, DiagnosticABSTRACT
Las alergias mediadas por IgE (tipo 1) son enfermedades crónicas que afectan a más del 20% de la población en algunos países. Se analizaron muestras de un grupo de 55 trabajadores del IUPOLC, Caracas, Venezuela, que manifestaron presentar síntomas relacionados con Alergias tipo I, mediante el uso de un cuestionario especialmente diseñado para tal fin. En ichas muestras se determinó la IgE Total Sérica por ELISA (Dr. Fooke Laboratorien, Alemania) y simultaneamente se ensayó un panel de IgE específica compuesto por ácaros y hongos de conocida prevalencia local por la técnica de Allergy Screen® (r-biopharm, Alemania), en aras de calcular la sensibilidad diagnósticada de la IgE Total sérica como marcador para el diagnóstico de Alergias Tipo I ante el hallazgo de valores significativos de IgE Específica para los alergenos seleccionados. Se escogieron los valores de referencia de IgE Total utilizados en la mayoría de los laboratorios clínicos de Venezuela. El valor de sensibilidad diagnóstica obtenido en el estudio para la IgE Total sérica fue de 66,67%, con una especificada de 100%. Valor Predictivo VPP de 100%. Valor Predicitivo Negativo 61,29%. Se discutió la posibilidad de que este valor de sensibilidad pudiese ser incluso menor con la inclusión de mayor número de alergenos y/o pruebas de piel. En conclusión, la utilización de la IgE Total sérica como herramienta diagnóstica de primera instancia (tamizaje y/o screening) de alergia tipo I, debe estar acompañada de la historia clínica del paciente y la prescripción de otros ensayos como la IgE específica. Los laboratorios clínicos locales deben procurar la utilización de mejores esquemas de interpretación (valores de referencia) de la IgE Total sérica que contribuyan a un mejor diagnóstico de esta patología.
IgE mediated allergies (Type I)are chronic diseases that effect more than 20% the population in some countries. We analyzed 55 blood samples from workers of Universitary Institute of Scientific Police, IUPOLC Caracas, Venezuela, that presented Allergies related symptyoms at the moment ofthe study. We used a specially designed survey to register that information. We tested serum Total IgE by ELISA method and a specific IgE using an immunoblott nitrocellulose paner composed with mites and molds allergens of well know local prevalence, in order to calculate the diagnostic sensitivity of serum Total IgE as a marker for screening Type I Allergies compared with allergen sensitivities detected on the individuals. We selected the most common reference values for serum Total IgE used in Venezuela. The sensitivity obtained for serum Total IgE was 66,67% specificity 100%, Positive Predictive Value 100%, and Negative Predictive Value 61,29%. We discussed the possibility that the sensitivity obtained for Total IgE could be oven lower if more number of allergens and skin tests were included on the study. We conclude that the use of Total IgE as screening diagnostic tool for allergies must be used together with clinical history of the patient and other assays like i.e. Specific IgE. Local Clinical Laboratories should promote of better interpretation schemes (reference values) for Total IgE that actually helps to a better diagnosis of this disease.