This is an autoimmune reaction in which patients have antibodies that are activated by cold temperatures. This can cause agglutination or hemolysis at cold temperatures but at normal temperatures these patients are unremarkable. Under a specific thermal amplitude the patients may have myocardial infarction, renal failure, hemolytic anemia and thrombosis. It is necessary to keep patient above the temperature that agglutination occurs. Cardioplegia must be given warm.

    Patients should be tested at 4° C.
        if positive reaction,  should be re-tested at 15° C
        if no additional reaction no further testing needed.
     If test comes back positive at 15° C, testing should continue up until a reaction is not found.  It is imperative that the patient's temperature be maintained during the surgery above this amplitude.

Erlich Test:
In the finger test the index finger of the patient is isolated by a venous tourniquet and placed in a 4 degree ice bath for 15 minutes. A blood sample is taken and Hct is looked at for Hemolysis.
The palm test a ice cube is placed in the palm of the hand for 15 min. the hand is then checked for acrocyanosis.

Clinical Relevance

• Unusual for cold agglutinins to become clinically apparent in a patient unless under going hypothermic bypass.
• Most CPB cases are performed with tepid temperatures and cold agglutinins will possibly activate in cardioplegia circuit.
• Exposure with prolonged sludging, multi-organ infarction may occur.

• Consists of prevention of complement activation and ultimately of agglutination or hemolysis
• In case of cold agglutinins caused by acute infarction elective surgery should be postponed for several weeks.
• Use either normothermia or mild hypothermia with temperatures continuously maintained above thermal amplitude
• May want to use warm cardioplegia for myocardial protection.
• Possible initial washout of warm cardioplegia followed by cold and rewarming the heart with "warm shot" to prevent agglutination.