4020. Analysis on the reticulocyte count with reticulocyte index

Reticulocytes are young, immature red blood cells (erythrocytes) that are released into the bloodstream from the bone marrow. Reticulocyte count is used to determine their concentration in the blood and to calculate the reticulocyte index.

Reticulocytes are precursor cells of erythrocytes involved in the process of hematopoiesis. They make up 0.5–2% of all erythrocytes. They are formed and mature in the bone marrow, after which they enter the bloodstream, where they continue maturing and transform into mature erythrocytes within approximately 2 days. They are capable of transporting oxygen, although less efficiently than mature red blood cells.

When erythropoiesis is accelerated, the proportion of reticulocytes increases; conversely, when erythropoiesis slows down, their proportion decreases. In cases of accelerated erythrocyte destruction, the reticulocyte count may exceed 50%.

To assess the severity of anemia, the reticulocyte index should be used. It is calculated as: (Reticulocyte % × Patient’s hematocrit) / (45 × 1.85) where 45 is the normal hematocrit level, and 1.85 is the average number of days required for new reticulocytes to enter the peripheral blood. An index below 2 indicates decreased erythrocyte production activity, while an index above 2–3 suggests increased erythropoietic activity.

Reticulocyte count may be ordered when it is necessary to:

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: