Hereditary spherocytosis

The diagnosis of HS is made when there is:

• Increased red-cell turnover (reticulocytosis) with or without anemia

• Typical spherocytes on the blood smear

• Associated absence of an immune cause (negative direct antiglobulin test [DAT]).

Diagnosis according to severity[1]Eber SW, Armbrust R, Schroter W. Variable clinical severity of hereditary spherocytosis: relation to erythrocytic spectrin concentration, osmotic fragility, and autohemolysis. J Pediatr. 1990;117:409-16. http://www.ncbi.nlm.nih.gov/pubmed/2391596?tool=bestpractice.com

HS can be clinically classified according to the severity of the anemia and symptoms. The assessment of HS severity should be made when the patient is well.

Trait

• Hemoglobin: normal

• Reticulocytes <3%

• Bilirubin <1 mg/dL (<17 micromol/L)

• Splenectomy not required.

Mild

• Hemoglobin 11 to 15 g/dL

• Reticulocytes 3% to 6%

• Bilirubin 1 to 2 mg/dL (17-34 micromol/L)

• Splenectomy usually not necessary.

Moderate

• Hemoglobin 8 to 12 g/dL

• Reticulocytes >6%

• Bilirubin >2 mg/dL (>34 micromol/L)

• Splenectomy may be necessary before puberty.

Severe

• Hemoglobin <6 to 8 g/dL

• Reticulocytes >10%

• Bilirubin >3 mg/dL (>51 micromol/L)

• Splenectomy necessary, delay until >6 years of age if possible.