Reticulocyte Count

CPT: 85045
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Test Includes

Reticulocytes are expressed as a percentage in a total of 1000 RBCs.

Expected Turnaround Time

Within 1 day

Related Documents

Specimen Requirements


Whole blood


Tube fill capacity

Minimum Volume

500 μL for Microtainer™ (capillary) specimens (Note: This volume does not allow for repeat testing.)


Lavender-top (EDTA) tube


Invert tube immediately 8 to 10 times once tube is filled at time of collection.

Storage Instructions


Stability Requirements



Room temperature

1 day


3 days



Freeze/thaw cycles


Causes for Rejection

Hemolysis; specimen more than 72 hours old; clotted specimen; tube not filled with minimum volume; improper labeling; transfer tubes with whole blood; specimen diluted or contaminated with I.V. fluid; specimen drawn in any anticoagulant other than EDTA; specimen received with plasma removed

Test Details


Evaluate erythropoietic activity which is increased in acute and chronic hemorrhage, and hemolytic anemias; evaluate erythropoietic response to antianemic therapy


Caution should be exercised with recently transfused patients (reticulocytes may decrease on a dilutional basis due to transfusion).


Automated cell counter


Patients receiving a large number of blood transfusions

Additional Information

Reticulocytes stained with a fluorescent reagent can be differentiated from mature red cells and other cell populations by light scatter, direct measurements, and opacity characteristics when using an automated hematology analyzer equipped with reticulocyte counting technology.


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
005280 Reticulocyte Count 17849-1 005280 Reticulocyte Count % 17849-1

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