Donath-Landsteiner test

The Donath-Landsteiner (DL) test is a serologic test used to detect the presence of a biphasic hemolysin. This autoantibody is seen in patients with paroxysmal cold hemoglobinuria. The test relies on the characteristic cold binding of an IgG autoantibody with specificity to the P blood group antigen. This autoantibody causes complement-mediated red blood cell (RBC) lysis when warmed to body temperature. In this review, we describe the various methods for performing the DL test—namely a direct test, an indirect test, an indirect test with modifications such as the use of enzyme-treated RBCs and two stages, and an indirect antiglobulin DL test—and highlight the advantages and disadvantages of each. Our focus is on the indirect testing method as it is most commonly used in blood bank laboratories.