A cold agglutinin titer can be used to determine the strength of the cold agglutinin and can help determine clinical significance. The titers are performed at 4oC, RT, 37oC, and AHG. Titrations are done from 1:1 through 1:2048 dilutions using the patient's plasma and saline. Donor RBCs are then added and the combination is incubated for 2 hours and observed for agglutination.
Titers at 1:512 or greater at 4oC are considered clinically significant. Normal individuals have a titer less than 1:64.
