Cold agglutinins


10 mL blood in plain tube, collected, separated at 37°C, then transported to the laboratory.


Presence of agglutination after incubation of patient’s serum with washed red cells at 4°C, 20°C and 37°C.

Differential testing against cord and adult blood cells may indicate antibody specificity.


Problems with blood grouping, compatibility testing.

Investigation of positive Direct antiglobulin test, possible Autoimmune haemolysis.


Cold agglutinins found in (idiopathic) cold haemagglutinin disease, mycoplasma pneumonia (anti-I); some lymphomas (anti-I or anti-i); Infectious mononucleosis (anti-i).

Thermal amplitude and specificity are of clinical significance in relation to the risk of in vivo haemolysis.


Bain et al. Dacie and Lewis Practical Haematology. Eleventh edition. 2012.