TSH immunoassays employing scavenging reagents for cross-reacting endocrine glycoprotein hormone analogues

A method for performing a thyroid stimulating hormone (TSH) immunoassay, the method comprising the steps of:

• (a) inserting a fluid sample into a device comprising an immunosensor in a conduit, said immunosensor having a capture antibody to TSH;
• (b) dissolving a signal antibody into said fluid sample;
• (c) amending said fluid sample with scavenger beads for one or more of follicle stimulating hormone (FSH), luteinizing hormone (LH) and chorionic gonadotropin (CG);
• (d) forming a sandwich complex on said immunosensor, said complex comprising said capture antibody, TSH, and said signal antibody;
• (e) washing uncomplexed signal antibody from the immunosensor with a wash fluid;
• and
• (f) detecting a signal associated with said complexed signal antibody,
• wherein the scavenger beads are removed to a waste chamber downstream of the immunosensor prior to the detecting.