Inter-alpha inhibitor proteins

A method for quantifying Inter-alpha-Inhibitor (IαI) and Pre-alpha-Inhibitor (PαI) in a sample from a subject comprising:

• a) contacting the sample with a binding agent to produce an IαI or PαI binding agent complex, wherein the binding agent is bound to a support;
• b) contacting the IαI or PαI binding agent complex with a detection agent;
• and
• c) detecting an amount of the detection agent bound to the IαI or PαI binding agent complex
• wherein the IαI or PαI comprises at least one heavy chain selected from the group consisting of H1, H2, and H3 chain;
• wherein the binding agent comprises an antibody, and the detection agent comprises a ligand that binds to at least one heavy chain,
• thereby quantifying IαI and PαI in the sample.