Nephelometry is a laboratory technique that measures the level of proteins in blood, such as immunoglobulins, which help the body fight infections. It works by measuring the amount of light scattered by particles in a diluted blood solution - more scattered light indicates more protein is not dissolved. A nephelometer is used to quantify the scattered light and provide nephelometry values to assess immunological conditions like liver disease, rheumatoid arthritis, and lupus. Nephelometry allows accurate monitoring of protein levels to assist in treatment planning for conditions where proteins are actively consumed.