Which two instruments are used to quantify by precipitation of immune complexes?

Which two instruments are used to quantify by precipitation of immune complexes?

• A. Turbidimetry and Nephelometry
• B. Spectrophotometry and Chromatography
• C. Mass spectrometry and ELISA
• D. Gel electrophoresis and Western blot

Answer: (A)

When immune complexes form and precipitate, the solution becomes cloudy. That cloudiness can be translated into a quantitative signal using light-based measurements. Turbidimetry detects how much light is transmitted through the sample. The more precipitate present, the more light is blocked, so the transmitted light decreases in proportion to the amount of immune complex. Nephelometry, on the other hand, measures light that is scattered by the precipitated complexes at a specific angle. This scattered light increases as more immune complex forms, providing a sensitive quantification, especially at lower concentrations. Together, turbidity and light scattering provide direct ways to quantify immune complexes formed by precipitation, which is why these two instruments are used for this purpose. Other techniques listed don’t quantify by precipitation: spectrophotometry and chromatography aren’t based on measuring precipitation directly; mass spectrometry and ELISA rely on mass detection or enzyme-driven color changes rather than measuring a precipitate; gel electrophoresis and Western blot separate and identify proteins rather than quantify immune-complex precipitation.

When immune complexes form and precipitate, the solution becomes cloudy. That cloudiness can be translated into a quantitative signal using light-based measurements.

Turbidimetry detects how much light is transmitted through the sample. The more precipitate present, the more light is blocked, so the transmitted light decreases in proportion to the amount of immune complex.

Nephelometry, on the other hand, measures light that is scattered by the precipitated complexes at a specific angle. This scattered light increases as more immune complex forms, providing a sensitive quantification, especially at lower concentrations.

Together, turbidity and light scattering provide direct ways to quantify immune complexes formed by precipitation, which is why these two instruments are used for this purpose.

Other techniques listed don’t quantify by precipitation: spectrophotometry and chromatography aren’t based on measuring precipitation directly; mass spectrometry and ELISA rely on mass detection or enzyme-driven color changes rather than measuring a precipitate; gel electrophoresis and Western blot separate and identify proteins rather than quantify immune-complex precipitation.