Diagnosis
In a peripheral blood smear, the abnormally small red blood cells lacking the central pallor as seen in non-hereditary spherocytosis is typically more marked in hereditary spherocytosis. The number of immature red blood cells (reticulocyte count) will be elevated.
Other protein deficiencies cause hereditary elliptocytosis, pyropoikilocytosis or stomatocytosis.
In longstanding cases and in patients who have taken iron supplementation or received numerous blood transfusions, iron overload may be a significant problem, being a potential cause of cardiomyopathy and liver disease. Measuring iron stores is therefore considered part of the diagnostic approach to hereditary spherocytosis.
An osmotic fragility test can aid in the diagnosis. In this test, the spherocytes will rupture in mildly hypotonic solutions - this is due to increased permeability of the spherocyte membrane to salt and water. Although the osmotic fragility test is widely considered the gold standard for diagnosing hereditary spherocytosis, it misses as many as 25% of cases. Flow cytometric analysis of eosin-5′-maleimide-labeled intact red blood cells and the acidified glycerol lysis test are two additional options to aid diagnosis.
Read more about this topic: Hereditary Spherocytosis