Abstract: The application provides competition assays used to detect free-light chains or intact immunoglobulins comprising incubating the sample with anti-FLC antibody, or heavy chain class-light chain type-specific antibodies, or fragments of such antibodies, and a known amount of FLC or intact immunoglobulin and detecting the binding of the antibody to the known amount of FLC or immunoglobulin. Assay kits and methods of producing particles coated with FLC are also provided.

Abstract: The invention provides a method for characterising a plasma cell associated disease in a patient comprising: (i) providing at least one sample from the patient; (ii) determining in the sample(s) two or more of; (a) the ?:? free light chain (FLC) ratio; (b) the ratio of ? light chains bound to a class of heavy chain:? light chain bound to the same class of heavy chain (HLC?:HLC ? ratio); (c) the total amount of FLC in the samples and (d) the total amount of ? light chains bound to the heavy chain class plus ? light chains bound to the same heavy chain class (total HLC); (iii) comparing each ratio or amount from (a) (b), (c) and/or (d) to predetermined values and assigning a score to each amount or ratio; and (iv) using the scores to characterise the plasma cell associated disease. Apparatus configured to carry out the method of the invention are also provided.

Abstract: The application provides competition assays used to detect free-light chains or intact immunoglobulins comprising incubating the sample with anti-FLC antibody, or heavy chain class-light chain type-specific antibodies, or fragments of such antibodies, and a known amount of FLC or intact immunoglobulin and detecting the binding of the antibody to the known amount of FLC or immunoglobulin. Assay kits and methods of producing particles coated with FLC are also provided.