Cryoglobulins are abnormal and antibody proteins called immunoglobulins in medical terms. Cryoglobulins precipitate and separate out from the blood solution when the temperature goes below 98.6°F (37°C). Precipitated cryoglobulins reduce the flow of blood, and can block the minute blood vessels. Presence of acute quantities of Cryoglobulin in the blood stream may be normal, but it is generally associated with an abnormal rate of protein production due to some prevailing medical condition, and can cause symptoms such as rashes, joint pain and weakness. To accurately diagnose the medical disorders associated with increased levels of cryoglobulins in blood, it becomes mandatory to test the relative quantity of cryoglobulins present in the blood stream.