Calc Function

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    Chief Complaint


    Organ System


    Patent Pending

    Absolute Reticulocyte Count & Reticulocyte Index

    Assesses appropriate response to anemia, frequently in sickle cell patients.
    When to Use
    Why Use

    Determining if an anemic patient is mounting an appropriate response to their anemia, or if they have an inadequate marrow response (either from the marrow itself or a nutrient deficiency, or the blood loss was too rapid for reticulocyte response).

    The laboratory “reticulocyte count” is actually a percentage. The absolute count corrects for the level of anemia, and the reticulocyte index determines if the reticulocyte count is appropriate for the level of anemia.



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    Next Steps
    Creator Insights


    • Patients with an appropriate marrow response (high reticulocyte index) typically are not evaluated further.
    • Patients with an inappropriate marrow response (low reticulocyte index) may be further evaluated for nutritional deficiencies or marrow abnormalities.
    • Always consider transfusion and/or iron supplementation in anemic patients.


    Absolute reticulocyte count = # or % retics * (pt's Hct / normal Hct)

    Reticulocyte index = absolute reticulocyte count / maturation factor

    Maturation factors:

    Hematocrit Maturation factor
    ≥35% 1.0
    25 to <35% 1.5
    20 to <25% 2.0
    <20% 2.5

    Facts & Figures


    Reticulocyte index Interpretation
    ≥2 Adequate response
    <2 Hypoproliferation
    Poorana Priya

    About the Creator

    Poorana Priya is a postgraduate pathologist practicing in India at Sree Balaji Medical College & Hospital.