| Definition: |
A test that measures the presence of cryoglobulins in the blood. Cryoglobulins are abnormal proteins. They become insoluble to varying degrees at temperatures below 37 degrees C (98.6 degrees F). Cryoglobulins form complexes that precipitate if blood is cooled and then rewarmed. Exposure of the face or hands, for example, of people with cryoglobulins can cause formation of precipitates that can block small blood vessels.
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| How the test is performed: |
Adult or child:
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood). A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
Infant or young child:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
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| How to prepare for the test: |
Adults:
There are no special preparations.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
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| How the test will feel: |
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
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| Why the test is performed: |
This test is most often performed when symptoms indicate that a person's blood may contain cryoglobulins. Cryoglobulins are associated with several disorders (see "What do abnormal results mean").
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| Normal Values: |
No presence of cryoglobulins in the blood is normal.
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| What abnormal results mean: |
A positive test may indicate:
Additional conditions under which the test may be performed:
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| What the risks are: |
- excessive bleeding
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fainting or feeling light-headed
- hematoma (blood accumulating under the skin)
- infection (a slight risk any time the skin is broken)
- multiple punctures to locate veins
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| Special considerations: |
There are many specific sub-types of cryoglobulins, and tests may determine the specific type present.
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
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