Multi-analyte diagnostic test for thyroid disorders

A method for analyzing a single patient sample to simultaneously determine levels of thyroid stimulating hormone and thyroxine, said method comprising:

• (a) incubating said sample with a mixture of particles comprising magnetically responsive material in a first suspension, said mixture of particles comprised of groups (i) and (ii):
• (i) particles coated with anti-thyroid stimulating hormone, and
• (ii) particles coated with anti-thyroxine,
• the groups distinguishable from each other by a flow cytometry-distinguishable characteristic that is independent of the coatings of subparagraphs (i) and (ii);
• (b) recovering said particles from said first suspension by subjecting said suspension to a magnetic field to cause said particles to adhere to a reaction vessel wall, and incubating said recovered particles with a mixture of labeled binding members capable of binding to the recovered particles in a second suspension, said mixture of labeled binding members comprising:
• (1) labeled anti-thyroid stimulating hormone, and
• (2) a labeled analog toward which anti-thyroxine has immunological binding affinity, but in which said immunological binding affinity is less than that of anti-thyroxine toward thyroxine;
• and
• (c) recovering said particles from said second suspension by subjecting said suspension to a magnetic field to cause said particles to adhere to a reaction vessel wall and detecting the amount of label bound to said particles thus recovered while correlating by flow cytometry the amount of label thus detected to the group to which said label is bound, thereby simultaneously obtaining values individually representative of the levels of thyroid stimulating hormone and thyroxine.