Howell‐Jolly body counting as a measure of splenic function. A reassessment

Summary Non‐surgical and surgical asplenia predisposes to fatal infections; therefore, simple, non‐invasive and repeatable tests for assessing splenic function are required, even in non‐specialized medical institutions. Howell‐Jolly bodies are the most characteristic peripheral blood abnormality after splenectomy, but their counting is not considered a reliable measure of splenic function. In this study, in a group of splenectomized subjects and of patients with non‐surgical hyposplenism, we have compared counting of Howell‐Jolly bodies, stained by both the May‐Grünwald/Giemsa method and the Feulgen reaction, with pitted cell counting which is considered a reliable technique for the assessment of splenic hypofunction. A significant correlation has been found between Howell‐Jolly body counts, stained by either technique, and pitted cell counts (P < 0.0001). Though Howell‐Jolly bodies were never detectable when pitted cell counts fell between 4 and 8%, values consistent with a very mild splenic hypofunction, for pitted cell counts above 8% their increase was always associated with increasing Howell‐Jolly body counts. These data suggest that, although pitted cell counting represents a more sensitive method for evaluating splenic function, Howell‐Jolly body counting may still be regarded as a simple and reliable technique for identifying and monitoring those cases associated with a real risk of overwhelming infections. Copyright © 1990, Wiley Blackwell. All rights reserved