TITER in its most simplist definition. Is a measurement of dilution represented by the ratio of dilution. In this case blood or serum, diluting it with saline.
For an example; diluting 1 part of blood with 32 parts of saline would equal a TITER of 1:32
CAD blood has a higher than normal amount of Cold Agglutinin autoantibodies (IgM). These autoantibodies, when exposed to cool/cold incorrectly attach to Red Blood Cells, thinking the Red Cells are a foreign invader, causing them to clump together (Agglutination), burst and die.
Titer in the case of CAD, is the number of dilutions in which the antibody is still able to cause agglutination.
The test to check for this, is listed differently by various names depending on the facility/lab. A few are listed below.
Quest – Cold Hemagglutinins
Labcorp Labs- Cold Agglutinin Titer, Quant (Quant = Quantitative )
ARUP Labs -Cold Agglutinins
CPL Labs – Cold Agglutinin, Quant (Quant = Quantitative )
In the case of testing the Cold Agglutinin TITER of a CAD, the lab techs watch for clumping (Agglutination) and at what ratio of dilution the clumping occurs.
Samples that indicate a Titer of 1:32 or less, are considered non-diagnositic [Negative], but do not necessarily exclude a diagnosis.
This test is always used in conjunction with results from other related tests. Depending on what might be a suspected cause that must be confirmed, or eliminated, when perusing a diagnosis.
Any result above 1:32 is considered “Positive” (some labs differ slightly). Some sources indicate a Titer of 1:64 and higher is an indicator of positive Cold Auto Immune Hemolytic Anemia (CAD). But this test is only a piece of other testing that must be done to draw conclusions.
Those with Cold Auto Immune Hemolytic Anemia, (showing a low Hgb and most likely a high Retic) and experiencing notable visible symptoms are usually in the TITER range of over 1:1,024, and could range as high as 1:500,000? This info can even vary based on the source you look at.
We suspect at lower but “positive” Titers (something above 1:64 but less than 1:1000). Some CADs may be unaware of their conditions until some type of blood test starts showing up as abnormal. Perhaps Agglutination notes on a otherwise normal looking CBC/RBC, etc?
Some long term CADs at 1:256 have documented they have no physical symptoms, reporting they have normal Hgb, and also normal Retic levels.
Those CADs suffering from being really reactive to the cold, and dealing with many physical symptoms, tend to have an alarmingly higher (tens of thousands) Titer.
This is one of the tests similar to CBC/RBC that may be difficult to run/result for the more cold reactive CAD. Collection at a satellite facility and shipped to a lab may fail or result incorrectly. “Keep It Warm” Techniques are most likely necessary for true CADs? Get retested if you don’t believe, or question, the results of one test. It may be a lab malfunction. Have the test done where they are aware, they keep your blood sample warm. and it is tested immediately “in-house”.