<prompt> Donath landsteiner test is used in diagnosis of ?-Paroxysmal nocturnal hemoglobinuriaParoxysmal cold hemoglobinuriaMarch hemoglobinuriaFavism  <response>: Paroxysmal cold haemoglobinuria PCH. In PCH, cold antibody is an IgG antibody Donath-Landsteiner antibody which is directed against P blood group antigen and brings about complement-mediated haemolysis. Attacks of PCH are precipitated by exposure to cold. PCH is uncommon and may be seen in association with teiary syphilis or as a complication of ceain infections such as Mycoplasma pneumonia, flu, measles and mumps HARSH MOHAN Text book of pathology 6th edition pg no 313 