Patent ID: 7491553

Claim:
A homogeneous immunoassay method for allergy testing comprising simultaneously detecting and quantifying immunoglobulin E (IgE) antibodies specific to a plurality of allergens in a serum sample, wherein the detecting and guantifying comprises: (a) contacting an undiluted serum sample from an individual with a plurality of labeled particles to create an allergic response mixture, wherein the labeled particles are coupled to from 2 to 100 specific types of allergens, each specific type of allergen having its own subset of labeled particles, each subset of labeled particles having a label that is specific to a specific type of allergen to enable identification and measurement of antibodies bound to the specific types of allergens, wherein the contacting occurs under conditions whereby immunoglobulin antibodies present in the serum sample bind specifically to one or more of the allergens; (b) thereafter contacting the materials from step (a) with a first conjugate comprising an anti-human IgE antibody conjugated to a first member of a specific binding pair; (c) thereafter contacting the materials from step (b) with a second conjugate containing a fluorophore moiety bound to a second member of the specific binding pair, wherein the second member of the specific binding pair has an affinity for binding to the first member of the specific binding pair; and (d) thereafter determining the amounts of specific the immunoglobulin antibody attached to the allergens in the materials from step (c) by simultaneously identifying the fluorescent emission signals that are specific to each of the labeled particle subsets and measuring the intensity of fluorescent emission signals of the fluorophore moiety in each subset; wherein, the first conjugate and the second conjugate are preselected to enable detection of anti-human IgE antibodies at a detection sensitivity ranging from about 10 −9 g/ml to about 10 −12 g/ml, and the undiluted serum is limited to having a volume of about 1 μL to about 25 μL, wherein the first conjugate comprises an anti-human antibody coupled to biotin or digoxin in which the molecular ratio of anti-human antibody to biotin or digoxin in the first conjugate is from about 1:10 to about 1:30, and wherein the second conjugate has a molecular weight of between about 400,000 and about 1,000,000 Daltons, wherein the selection of the first conjugate, second conjugate, and the serum volume has the function of avoiding quenching of fluorescence and high dose hook effects; and wherein, the detection sensitivity ranging from 10 −9 to 10 −12 g/ml is measured under homogeneous assay conditions.