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Test Code RETC Reticulocyte Count

Specimen Type



Lavender top, EDTA

Turnaround Time

24 hours

STAT Days and Times Performed


Days and Times Performed


Method Name

Automated method and Manual methods

Automated method - Sysmex XN automated hematology analyzer

Manual method - new methylene blue stain

Test Includes

Percent Retic, Absolute Retic, Retic Production Index and Retic Hemoglobin Content

Preferred Volume

4 mL

STAT Turnaround Time

1 hour

Fee Code


Test Limitations

Refrigerate sample if transportation is delayed. Transportation temperature: specimen cannot be frozen or heated

Rejection criteria: clotted or short specimen volume, microclot formation, improper tube

Specimen must be received within 8 hours of collection.


Specimen Minimum Volume

  • 2 mL blood in 4 mL tube
  • 1.5 mL blood in 3 mL tube.
  • If a microvette is collected, the minimum volume is 250 µL



Reference Values


Age Retic Percent (%) Retic Absolute
Retic Hemoglobin
Content (PG)
  Male & Female Male & Female Male Female Male Female
Adult 0.5 -1.5   22.4-88.7 19.4-78.9 30.0-37.5 27.7-37.6
At birth 1.8-4.6 70.2-252.8     21.9-35.4 20.2-29.1
1 week 0.1-0.9 3.9-56.4     21.9-35.4 20.2-29.1
1 month 0.1-1.7 3.0-91.5     21.9-35.4 20.2-29.1
3-5 months 0.4-1.0 12.4-44.5     21.9-35.4 20.2-29.1
6-11 months 0.7-2.3 25.9-121.44     21.9-35.4 20.2-29.1
1 year 0.6-1.7 23.4-89.8     21.9-35.4 20.2-29.1
2 years 0.5-1.0 19.5-52.8     24.9-35.1 22.7-30.0
2 years to 12 years 0.5-1.5 20.0-77.8     27.0-36.2 24.3-31.6


The reticulocyte count includes a percent reticulocyte count, absolute reticulocyte count and reticulocyte production index (RPI). The absolute reticulocyte count is reported to give a more meaningful expression of erythropoiesis. The RPI is a helpful guideline to determine whether the marrow is responding appropriately to anemia. In a patient with anemia, the retic percentage reflects not only the level or marrow erythroid production, but also the fact that the retics are diluted by fewer red  cells. Thus, the retic percent may be relatively increased even the marrow is not responding appropriately.

The Ret-HE can help establish a diagnosis of iron deficiency anemia (IDA) and monitor therapy when combined with additional iron studies such as serum ferritin. The RET-HE is below normal in 80% of cases of IDA but within normal range in more than 80% of cases of anemia of chronic inflammation. The RET-HE cannot be used to distinguish IDA from thalassemia trait, however, because the RET-HE values are low in both diseases.

Reference ranges confirmed November, 2009