Febrile--cold agglutinins

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.

The sample is collected in a tube that has been warmed to normal body temperature (98.6 degrees F) and sent to a laboratory.

How to Prepare:
Adults:
There is no special preparation.

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 experience, 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:



How it Feels:
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 .

Risks:

  • excessive bleeding
  • fainting or feeling lightheaded
  • hematoma (blood accumulating under the skin)
  • infection (a slight risk any time the skin is broken)
  • multiple punctures to locate veins



Why this Test is Performed:
The antibodies appear in the blood after infections by a variety of microorganisms. Atypical pneumonia and viral infections can be detected by testing for cold agglutinins.

Normal Values:

  • febrile (warm) agglutinins: no agglutination in titers at or below 1:80
  • cold agglutinins: no agglutination in titers at or below 1:16



Abnormal Results:
The presence of febrile agglutinins may occur after:

The presence of cold agglutinins may occur after:



Cost:
The estimated cost is $28.

Special Considerations:
If cold agglutinin disease is suspected, the individual needs to be kept warm.


After a blood donation, tests may be performed on the blood. This particular test is for ABO blood typing.