RBC Band 3 Protein Reduction in Hereditary Spherocytosis

Hereditary spherocytosis is a common genetic disorder that causes congenital hemolytic anemia through the production of structurally compromised spherical red blood cells (spherocytes). The severity of the disease varies widely; most cases are classified as moderate and present with symptoms such as anemia, jaundice, and splenomegaly. Depending on the level of severity, a diagnosis of hereditary spherocytosis can rule out other causes of hemolytic anemia. 

Hereditary spherocytosis is diagnosed based on family history and clinical features, along with laboratory tests. This test assesses for band 3 (solute carrier family 4 member 1 [SLC4A1]) protein, the most abundant transmembrane protein in human RBCs. Eosin-5-maleimide (EMA) dye is used to mark band 3 on intact RBCs. A reduction of fluorescence intensity will be observed in hereditary spherocytosis. A reduction in fluorescence intensity may also be observed in other rare disorders, specifically congenital dyserythropoietic anemia type II, Southeast Asian ovalocytosis, and hereditary pyropoikilocytosis.

Test Interpretation

Sensitivity/Specificity

Clinical sensitivity: 93%

Analytic sensitivity/specificity: unknown

Results

Limitations

Recent transfusion (within the last three months) may affect test results; correlation with clinical and other laboratory findings is strongly recommended.