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Test Code RETC Reticulocyte Count

Specimen Type



Lavender top

Preferred Volume

4 mL



Turnaround Time

24 hours

STAT Availability


Test Methodology

New methylene blue stain, Automated and Manual methods

CPT Code


Test Includes

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

STAT Turnaround Time

1 hour

Reference Range


Age Retic Percent (%) Retic Absolute (K/uL) 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

Minimum Volume

2 mL in 4 mL tube, 1.5 mL in 3 mL tube mL

Fee Code