What Is a Cold Agglutinins Test?

Medically Reviewed by Carol DerSarkissian, MD on May 29, 2023
3 min read

Most people do not like cold weather. After all, it conjures up images of howling winds, sleet, icy roads, and the flu or a bad head cold.

But you might have more reasons for not liking cold temperatures if you have a rare condition known as “cold agglutinin disease.”

Cold agglutinins are antibodies that, instead of helping to fight bad things like bacteria in your body, attack your red blood cells. When your red blood cells are targeted by the cold agglutinins, the cells react by clumping together when it gets cold. This happens in the lab when your blood is exposed to temperatures between 30 F and 50 F.

Antibodies are special proteins in your body that usually attack invaders like viruses or bacteria. But in someone with cold agglutinin disease, when they are exposed to cold temperatures, these proteins clump up and attach to and destroy red blood cells instead. This can lead to anemia as well as other signs and symptoms.

Your doctor may order a test for cold agglutinins if you have symptoms of the disease. They can included:

This is a blood test that measures the amount of cold agglutinins in your blood. The test may also be done while the blood sample is exposed to different temperatures; this helps the doctor figure out at what temperature your red blood cells start to clump together.

There is nothing you need to do in advance to prepare. A nurse or medical assistant will clean your skin, usually just above the bend of an elbow. They’ll then draw the blood from your arm with a needle. The whole process will only take a couple of minutes.

After your blood has been taken, it will be diluted and spread among a number of test tubes. Your blood sample will then be cooled at a variety of low temperatures to determine if, and when, the clumping of red blood cells happens.

Your doctor may want you to have it if they suspect that you have cold agglutinin disease. Its symptoms can be a sign of many conditions.

One of these conditions is called hemolytic anemia, which means that your red blood cells aren’t living as long as they normally do. It can be caused by too many cold agglutinins in the blood. Along with the other symptoms of cold agglutinin disease, hemolytic anemia could lead to problems like irregular heartbeats or an enlarged heart.

Cold agglutinins are found in almost everyone’s blood, but in high numbers they can lead to cold agglutinin disease. This can be the result of such things as certain infections, autoimmune diseases or cancers.

After your doctor gives you the results of the cold agglutinins test, they will discuss a treatment plan with you, depending on what the test revealed. They may want you to have more tests, based on the results.

One step you can take to help ease some of the symptoms is to avoid lowering your body temperature. For example:

  • Stop eating cold foods and drinking cold drinks.
  • Keep the temperature of your home warm.
  • Don’t take cold showers.
  • Bundle up if it's chilly outside.