Cryoglobulins are abnormal proteins. This article describes the blood test used to check for them.
In the laboratory, cryoglobulins come out of blood and form crystals when the blood sample is cooled below 98.6 degrees Fahrenheit (37 degrees Celsius).
Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.
Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.
Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.
Because they are temperature sensitive, cryoglobulins are very hard to accurately detect. The blood specimen must be collected in a special way and the test should only be done in laboratories that are equipped for it.
There is no special preparation for this test.
Some people feel discomfort when the needle is inserted. Afterward, there may be some throbbing.
This test is most often done when a person has symptoms of a condition associated with cryoglobulins. Cryoglobulins are associated with cryoglobulinemia, but they also occur in other conditions that affect the skin, joints, kidneys, and nervous system.
© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885