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Test Catalog

Test ID: EEEVI    
Red Blood Cell (RBC) Enzyme Interpretation

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

Interpretation of results for the red blood cell enzyme evaluation

 

Identifying defects of red cell enzyme metabolism

 

Evaluating patients with Coombs-negative hemolytic anemia

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

Erythrocyte enzyme deficiencies are inherited causes of hemolytic anemia. Some are very common, such as glucose 6-phosphate dehydrogenase (G6PD) deficiency, and others are very rare, found in only a few families around the world. Most are autosomal in inheritance, but some are sex-linked and located on the X chromosome. Most enzyme deficiencies result in chronic nonspherocytic hemolytic anemia of variable severity; however, some, such as G6PD, can be hematologically normal with episodic acute hemolysis due to a trigger event such as medications, toxins, or some foods. The RBC enzymopathies do not typically show recurrent pathognomonic changes on the peripheral blood smear other than generic features of hemolytic anemia, although some such as pyruvate kinase deficiency can have echinocytes and pyrimidine 5' nucleotidase (P5NT) deficiency is associated with basophilic stippling. RBC enzyme activity levels are best evaluated as a panel as reticulocytosis can mask some deficient states and comparison to the background enzyme activity is useful.

 

This is a consultative evaluation of red cell enzyme activity as a potential cause of early red cell destruction.

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.

Only orderable as part of a profile. For more information see EEEV1 / Red Blood Cell (RBC) Enzyme Evaluation, Blood.

 

Definitive results and an interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

A hematopathologist expert in these disorders evaluates the case and an interpretive report is issued.

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

Recent transfusion may mask the patient’s intrinsic enzyme activity and cause unreliable results.

 

A very high white blood cell count can contribute to interference and falsely raise the activity for some enzymes.

 

Some enzyme deficiency disorders can be masked by reticulocytosis and comparison of activities of other RBC enzyme activities in this panel can be useful.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Koralkova P, van Solinge WW, van Wijk R: Rare hereditary red blood cell enzymopathies associated with hemolytic anemia - pathophysiology, clinical aspects, and laboratory diagnosis. Int J Lab Hematol. 2014 Jun;36(3):388-397

2. Beutler E: Glucose-6-phosphate dehydrogenase deficiency and other enzyme abnormalities. In: Beutler E, Lichtmann MA, Coller BS, Kipps TJ, eds. Hematology. 5th ed. McGraw-Hill Book Company; 1995:564-581