How to use Donath-Landsteiner test to diagnose paroxysmal cold haemoglobinuria (PCH).

Paroxysmal cold haemoglobinuria (PCH) accounts for around a third of cases of autoimmune haemolytic anaemia in children. PCH is caused by an autoantibody that fixes complement to red cells at low temperatures and dissociates at warmer temperatures (a biphasic haemolysin), triggering complement-mediated intravascular haemolysis. Named the Donath-Landsteiner (D-L) antibody after its discoverers, it is usually formed in response to infection and demonstrates specificity for the ubiquitous red cell P-antigen.