Utility: Functional evaluation of neutrophil phagocytosis.
Specimen: 1 - 4 mL peripheral blood in sodium heparin (green top).
CPT codes: 86344 x 2, 88187.
Clinical indication/general description
Primary neutrophil disorders are associated with recurrent bacterial infections, abnormal pus formation and poor wound healing. Neutrophils must migrate through tissues and phagocytose the invading organisms, a process that requires actin polymerization. A variety of disorders may be associated with the inability of neutrophils to migrate and phagocytose bacteria, such as neutrophil actin dysfunction disorder and Wiskott-Aldrich syndrome. In addition, a variety of drugs and other extrinsic factors can affect the phagocytic function of neutrophils.
A flow cytometric-based assay is used to measure the phagocytosis of bio-particles coated with E. coli or S. aureus by neutrophils. The particles are conjugated to pHrodo, a novel fluorescent dye that dramatically increases in fluorescence when internalized within the neutrophil. After incubation of the bioparticles with the patient's neutrophils, emission of fluorescence indicates normal phagocytosis.