What is the role of the complement lysis sensitivity test in the workup of paroxysmal nocturnal hemoglobinuria (PNH)?

Updated: May 20, 2021
  • Author: Emmanuel C Besa, MD; Chief Editor: Sara J Grethlein, MD, FACP  more...
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Answer

The complement lysis sensitivity test of Rosse and Dacie is a more precise method for diagnosing PNH. RBCs are sensitized with a potent lytic anti-I antigen and hemolyzed with limiting amounts of normal serum as a source of complement. [26, 27, 28] This demonstrates threee groups of RBCs in patients with PNH, including the following:

  • PNH I cells are normal in sensitivity to complement

  • PNH II cells are moderately more sensitive to complement than normal cells

  • PNH III cells are markedly sensitive to complement, requiring one fifteenth to one twentieth of the amount of complement for an equal degree of lysis; this group of cells is increased in patients with more severe PNH, and it is associated with a mean life span of 10-15 days


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