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.