What method is commonly used to measure large particles like antigen-antibody complexes?

Nephelometry and turbidimetry are both well-established methods used to measure large particles, including antigen-antibody complexes, in a solution.

Nephelometry specifically measures the scattered light produced by particles suspended in a solution. When a light beam passes through a sample containing these complexes, particles scatter the light in various directions. The intensity of the scattered light at a specific angle is proportional to the concentration of these particles, making nephelometry an effective tool for quantifying antigens and antibodies.

Turbidimetry, on the other hand, measures the reduction in intensity of light transmitted through a sample due to scattering caused by particles. As the concentration of particles increases, more light is scattered and less light passes through the solution. This method provides an indirect way of determining the concentration of particles based on the amount of light that is blocked.

Both methods are commonly employed in clinical chemistry for quantifying large molecular complexes, providing valuable insights into various conditions based on the levels of these complexes in bodily fluids. Therefore, the correct answer encompasses both nephelometry and turbidimetry, highlighting their shared utilization in measuring large particles such as antigen-antibody complexes.