Application of differential light scattering to the latex agglutination assay for rheumatoid factor.

When a suspension of particle is irradiated with a collimated beam of monochromatic polarized light of a wavelength close to the particle size and the intensity of the scattered light is measured as a function of angle, the scatter intensity is characterized by a series of relative maxima and minima. The nature of the signal depends on several significant variables that are characteristic of the particles. We have constructed a differential light scatter photometer and have applied the technique to analysis of rheumatoid factor by using latex particles coated with fraction II gamma-globulin. The results suggest that such a photometer may have potential applications in antigen-antibody assays based on the use of sensitized particles.