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Interpretive Handbook

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Test 81087 :
Hereditary Spherocytosis Evaluation

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

The hemolytic anemias are a group of anemias that are characterized by an increased destruction of red blood cells (RBC). Anemias may be divided into inherited or acquired. Hereditary spherocytosis (HS), also known as congenital hemolytic anemia, is inherited as a non-sex-linked dominant trait. HS is caused by a RBC membrane defect. The RBCs are spherocytic in shape and show an increased rate of destruction. HS can result from abnormalities involving several red cell membrane proteins, such as band 3, spectrin, and ankyrin.

 

Most often HS is diagnosed in childhood, adolescence, or early adult life. The diagnosis of HS is usually made by a combination of patient and family history, laboratory evidence of hemolysis, and review of a peripheral blood smear. The osmotic fragility test is usually markedly abnormal in these cases. However, factors such as age, sex, and medications can affect the osmotic fragility test.

 

This evaluation combines osmotic fragility testing with a newly developed flow cytometry assay to provide complementary information in the evaluation of patients with suspected HS.

Useful For Suggests clinical disorders or settings where the test may be helpful

Investigation of suspected hereditary spherocytic hemolytic anemia

Interpretation Provides information to assist in interpretation of the test results

An interpretive report will be provided.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Interfering factors:

-Recent transfusion

-Oral contraceptives

-H2 blockers

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

0.50 g/dL NaCl (unincubated)

Males: 0.0-47.8% hemolysis

Females: 0.0-31.1% hemolysis

 

0.60 g/dL NaCl (incubated)

Males: 18.7-67.4% hemolysis

Females: 10.9-65.5% hemolysis

 

0.65 g/dL NaCl (incubated)

Males: 4.4-36.6% hemolysis

Females: 0.2-39.3% hemolysis

 

0.75 g/dL NaCl (incubated)

Males: 0.8-9.1% hemolysis

Females: 0.0-10.9% hemolysis

 

An interpretive report will be provided.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Gladen BE, Luicens JN: Hereditary spherocytosis and other anemias due to abnormalities of the red cell membrane. In Wintrobe's Clinical Hematology. Tenth edition. Edited by GR Lee, J Foerester, J Lukens, et al. Baltimore, Williams and Wilkins, 1999 pp 1132-1159

2. Gallagher PG, Jarolim P: Red cell membrane disorders. In Hematology: Basic Principles and Practice. Third edition. Edited by R Hoffman, EJ Benz, SJ Shattil, et al: New York, Churchill Livingstone, 2000 pp 576-610


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