Neutrophil CD64: a diagnostic marker for infection and sepsis.

Neutrophilic granulocytes express Fcgamma receptor (FcgammaR) [cluster of differentiation 64 (CD64) antigen] only when they are activated. Neutrophil CD64, demonstrated using flow cytometry, can be used as a diagnostic marker of infection and sepsis. Neutrophil CD64 is superior to C-reactive protein and hematological determinations for detecting systemic infection or sepsis, since it combines high sensitivity (90% or more) with high specificity (90%-100%) in both adults and children. In addition, the test performs well in distinguishing infection from flares in autoimmune inflammatory diseases and has somewhat more limited utility for differentiating bacterial from viral infection. This review summarizes the available literature regarding CD64 as a marker of infection, and outlines future clinical studies for confirming the diagnostic performance of this promising marker.