A variety of basic assays are used to detect autoantibodies. Nephelometry is based on the principle of:
Light attenuated in intensity by scattering
Refraction of light
Reduced transmission of light
Filtration of solutes by kidney
Nephelometry measures the interaction of antibodies and antigens in solution, detecting immune complex formation by monitoring changes in the scattering of an incident light. Ref: Imboden J.B. (2007). Chapter 3. Laboratory Diagnosis. In J.B. Imboden, D.B. Hellmann, J.H. Stone (Eds), CURRENT Rheumatology Diagnosis & Treatment, 2e.