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RBC Band 3 Protein Reduction in Hereditary Spherocytosis

2008460

RBC Band 3 Protein Reduction in Hereditary Spherocytosis 2008460

Method

Qualitative Flow Cytometry

Use to confirm a diagnosis of hereditary spherocytosis when hemolytic anemia and spherocytes are present.

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

Test Result	Interpretation
Normal	Normal staining of band 3 protein with EMA Does not suggest hereditary spherocytosis
Abnormal	Decreased staining of band 3 protein with EMA Provides evidence for hereditary spherocytosis (or more rarely, dyserythropoietic anemia type II, Southeast Asian ovalocytosis, or hereditary pyropoikilocytosis)
Equivocal	Unclear whether the level of band 3 protein staining with EMA is normal Insufficient evidence to support or negate a diagnosis of hereditary spherocytosis

Test Result

Interpretation

Normal

Normal staining of band 3 protein with EMA

Does not suggest hereditary spherocytosis

Abnormal

Decreased staining of band 3 protein with EMA

Provides evidence for hereditary spherocytosis (or more rarely, dyserythropoietic anemia type II, Southeast Asian ovalocytosis, or hereditary pyropoikilocytosis)

Equivocal

Unclear whether the level of band 3 protein staining with EMA is normal

Insufficient evidence to support or negate a diagnosis of hereditary spherocytosis

Limitations

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

References

28447420

Narla J, Mohandas N. Red cell membrane disorders. Int J Lab Hematol. 2017;39 Suppl 1:47-52.

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