What laboratory finding is indicative of hereditary spherocytosis?

The presence of increased mean corpuscular hemoglobin concentration (MCHC) along with the observation of spherocytes on a peripheral blood smear is indicative of hereditary spherocytosis. This genetic disorder affects the red blood cell membrane, leading to an abnormal shape of the cells. The spherocytes are less flexible and more prone to rupture, resulting in hemolytic anemia.

Increased MCHC is typically noted in this condition because the spherocytes have a higher hemoglobin concentration relative to their volume compared to normal red blood cells. Together, these findings support the diagnosis of hereditary spherocytosis, which is characterized by both the unique shape of the red blood cells and the associated hematologic changes.

Other options, such as decreased platelet count, low hemoglobin levels, or elevated white blood cell count, do not specifically highlight the hallmark features of hereditary spherocytosis and could be associated with various other conditions. Thus, the combination of increased MCHC and spherocytes on peripheral smear distinctly points towards hereditary spherocytosis.