Discrepancy between pit counting and spleen function tests in nutritional anemias and hemoglobinopathy C.

An increased percentage of erythrocytes with crater-like indentations (pits) when viewed under interference contrast microscopy is accepted as indicative of splenic hypofunction. The percentage of pitted erythrocytes was above the upper limit of the normal range (0.0-3.2%) in 6 patients with megaloblastic anemia (4.6-22.6%), 8 patients with iron deficient anemia (5.6-21.0%) and 6 patients with HbC diseases (12.5-45.0%). However, the spleen function was normal or hyperactive when evaluated by the rate of removal from the circulation of heat-damaged 99mTc-labeled autologous erythrocytes. Thus, in these diseases, there is a discrepancy between pit counting in the peripheral blood and other spleen tests.