Corrected Reticulocyte Count Calculator

Corrected reticulocyte count (CRC), sometimes called reticulocyte index (RI), is a parameter for bone marrow response assessment used in the diagnosis of anemia. The reticulocyte index of a healthy person should be between 0.5% and 2.5%.

If the patient has anemia (hemoglobin of less than 13 to 14 g/dL in males and 12 to 13 g/dL in females), a reticulocyte index of less than 2% does not indicate loss of red blood cells but decreased production of reticulocytes. Patients with an inappropriate marrow response may be further evaluated for nutritional deficiencies or bone marrow abnormalities.

A CRC of more than 3% in a person with anemia indicates loss of red blood cells (from causes such as destruction, bleeding, etc.), with increased compensatory production of reticulocytes to replace the lost red blood cells.

💡 See also our allowable blood loss calculator.

The CRC (corrected reticulocyte count) is calculated using this equation:

CRC = (Hematocrit / normal Hematocrit) × (Reticulocytes / Maturation)

• A value of 45% is most frequently used as normal hematocrit (normal Hematocrit), but you can change it by ticking the box in the reticulocyte index calculator.

• Maturation is a coefficient used to correct for the longer lifespan of prematurely released reticulocytes in the blood, which is a phenomenon of increased red blood cell production.

  This factor equals 1.0 for a hematocrit of 36%-45%, 1.5 for 26%-35%, 2.0 for 25%-16%, and 2.5 for a hematocrit of 15% or lower.

  You can see the assigned value by ticking the corresponding box.

1. Enter the patient's hematocrit (Hct) level in %.

2. Enter the reticulocyte level in %.

3. If you wish, change the value of normal hematocrit in %.

4. The calculated corrected reticulocyte count is provided in % in the last field.

After you've finished with this calculator, you might also be interested in our hematocrit hemoglobin ratio calculator.