A simple splenic reticuloendothelial function test: counting erythrocytes with argyrophilic inclusions.

The presently accepted methods for evaluation of splenic reticuloendothelial (RE) function include 99mTc sulfur colloid spleen scan, antibody-coated autologous erythrocyte clearance, and pocked erythrocyte count. All methods involve special equipment and/or risk and inconvenience to patients. A simple method of assessing splenic RE function was developed by counting erythrocytes with argyrophilic inclusions using a simple silver stain and an ordinary microscope. To test the validity of this method, blood samples were collected from patients suspected of having hyposplenia or asplenia, including patients with history of splenectomy, sickle cell disease or trait, and newborns. Blood samples were also collected from normal adults and from patients without hyposplenia or asplenia as controls. The samples were tested by this method and compared to the pocked erythrocyte count that served as a gold standard. The results obtained by the two methods were found to be very comparable with little overlap between those from controls and patients with definite hyposplenia or asplenia. With the pocked erythrocyte count as the gold standard, this method has a sensitivity of 88.9% and a specificity of 97.1%. However, this method requires no special equipment. Staining can be applied to fresh blood smears as well as to Wright-stained smears, and the silver-stained smears are permanent.