Development of allergen-coated paper discs for allergy diagnosis by ELISA

In vitro testing is useful for detecting pollen and fungal-allergen sensiti vities in nasobronchial-allergy patients. However, allergen-coated discs or solid-phases supplied in kits do not contain all the relevant extracts. Th e present study was aimed to develop a safe and credible procedure of aller gen coating on paper discs for allergy diagnosis by ELISA. Paper discs were coated with indigenous allergens using poly(vinyl alcohol) and glutaraldeh yde, ELISAs were carried out to standardize the allergen-coated discs using skin-test-positive-patients' sera, The cut-off value (A) for ELISA was wor ked out by analysing normal human sera (NHS) and is based on the mean+/-2 S .D. for the NHS value. The allergen-coated discs, i.e. Centre for Biochemic al Technology (CBT) discs, demonstrated excellent comparison with plate-bin ding method and Pharmacia discs [Prosopis juliflora (mesquite), critical va lue 0.879 at 5% probability+/-0.599, n = 11, is significant]. Inter- and In tra-assay coefficients of variations ranged from 2.5-14.05% to 4.8-11.5% wi th different allergens. Results of skin tests and ELISA with CBT discs show ed 60-70 % correlation.