Immunoglobulins, or cryoglobulins as they are known in medicine, are aberrant antibody proteins. When the temperature falls below 98.6°F (37°C), cryoglobulins precipitate and separate from the blood solution. Cryoglobulins that have precipitated constrict blood arteries and limit blood flow. Although the presence of small amounts of cryoglobulin in the bloodstream may be normal, it is typically accompanied with an excessive rate of protein synthesis brought on by an underlying medical problem. This can result in symptoms including rashes, joint discomfort, and weakness. It becomes necessary to measure the relative amount of cryoglobulins present in the blood stream in order to accurately detect the medical diseases connected to elevated levels of cryoglobulins in blood.