Cold agglutinins

Specimen:

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

Method:

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.

Application:

Problems with blood grouping, compatibility testing.

Investigation of positive Direct antiglobulin test, possible Autoimmune haemolysis.

Interpretation:

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.

Reference:

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