Also know as: Agglutinins, Cold Autoantibodies, or Cold-Reacting Antibodies

A blood test by one of the above names will check for conditions that will cause the body to produce specific types of antibodies called Cold Agglutinins.

Cold agglutinins are generally produced by the immune system when there is a suspected infection.

Cold temperatures, as well as infections, can trigger it in a CAD patient.  In the case of an infection compounded on top of CAD, things can get worse, and get worse at a more rapid pace.

This will cause red blood cells to cluster together [clump] at low temperatures.  That trigger temperature varies from CAD to CAD.

Higher than normal Cold Agglutinin Antibody levels in a normal person, usually isn’t cause for concern unless it remains after a period of time.

In a normal person the skin of the hands and feet might become pale, and perhaps numb, when exposed to cold.  Those symptoms will dissipate when the skin warms up.  There is normally no harm to the body.

Unlike a CAD.  In a CAD, they mostly experience their hands, feet, or nose becoming dark blue to almost black.  There may be no pain or discomfort in the initial stage.  But this is a serious health concern for a person with CAD.  Though the visible symptoms may go away, damage has taken place in the form of Hemolysis.  The degree of damage will vary based on several factors.

Higher levels of cold agglutinins when it comes to someone with Cold Agglutinin Disease [CAD],  can quickly damage red blood cells in the body.  This will cause a condition known as autoimmune hemolytic anemia.


This test measures the amount of Cold Agglutinins in the blood.  The test may be done while the blood is exposed to different temperatures.  The test result is reported as a Titer (a ratio of concentration).

A “Positive” value for the test is associated with a reaction taking place somewhere after the blood sample has been diluted with saline more than 32 times.

At a dilution of 32 times, that ratio would indicate a “Titer” of  1:32

Samples that indicate a Titer of 1:32 or less are nondiagnositic [Negative], but do not necessarily exclude a diagnosis.

Samples that indicate a Titer above 1:32 may indicate some of the following:

M. pneumoniae infection
Infectious Mononucleosis [Mono]
Multiple myeloma
Legionnaires disease
Hepatitis C

The results of this test are never taken as a “Stand alone” test.  The result must be used with additional testing and other information.

Those with Cold autoimmune hemolytic anemia:
Usually are in the TITER range of 1:1,024 to 1:512,000

If an infection is treatable, a non-CAD issue, the Titer will decrease after treatment.

Mycoplasma pneumoniae pneumonia might be suspected if:
There is an initial titer of 1:128, or there is a 4 times increase between the acute and convalescent sera.

Acute Sera is serum taken and tested while a patient is ill.
Convalescent Sera is serum taken after the patient recovers from an infection.  Usually about 4 weeks after treatment.

Falling Titer levels usually indicate a diagnosis and treatment worked.