The Absolute Reticulocyte Count Calculator counts the absolute number of reticulocytes and estimates the number of reticulocytes in a patient’s blood. In short, the values required for the calculation are the patient’s reticulocytes and their hematocrit percentage. Also, in the advanced mode, entering the desired normal hematocrit value is also possible.

In the following text, you can find out the number of red blood cells and estimate it the easiest. With our calculator, you can calculate the required values, and in addition to this, we have several different calculators that make it easier to determine different health related values without medical and clinical help. Also, read more about hematocrit on this Hematocrit to Hemoglobin Ratio Calculator. You should also check this US Health Savings post to get yourself educated and informed about it, but don’t miss this Adrenal Washout and EORTC posts as well.

Reticulocyte Count

The absolute number of reticulocytes is determined as a quantitative measure of the production of new red blood cells in the bone marrow. Thus, we use it as a marker in producing red cells and it helps differentiate between hypo and hyperproliferative anemias. To sum up the normal reticulocyte count in a healthy person is 26-130 cells/μL.

Further, high reticulocyte counts in anemic patients may indicate a corresponding increase in red blood cell production in response to chlorosis. Also we can describe very high blood counts as reticulocytosis. Elevated reticulocyte counts in peripheral blood are reliable indicators of regenerative erythropoiesis. As a result, reticulocytosis in combination with macrocytic anemia indicates partially treated vitamin B12 or folic acid deficiency.

Moreover, low reticulocyte counts indicate a reduced bone marrow response. So, the causes of low reticulocyte counts are: chemotherapy, aplastic anemia, pernicious anemia, malignant bone marrow tumors, problems with erythropoietin production, various vitamin and mineral deficiencies (iron, vitamin B12, folic acid), and chronic conditions (chronic anemia).

On the other hand, in very frail patients, the result may be wrong. So to have a better perspective and insight into the patient’s reticulocyte count, we advise you to consider our reticulocyte count calculator.

Reticulocyte Count vs. Absolute Reticulocyte Count

Determination of absolute or relative reticulocyte count and reticulocyte maturity index (RMI) are important indicators of erythropoietic activity of bone marrow. In addition, the determination of reticulocyte count is important in a normocytic anemia.

Reference values for men and women: 22 - 97 \times 109 / L \; or \; 5.0 - 21.6 \; rel / 103 \; Erc

Reticulocyte count indicates the ability of the bone marrow to produce mature erythrocytes. Without chlorosis, the normal reticulocyte count is 1% to 2%. Therefore, the increase in cells proves that the bone marrow responds adequately to chlorosis. When the bone marrow is significantly stimulated, erythrocytes with a nucleus can also be seen in the peripheral juice smear. It should be borne in mind that if erythrocytes with a nucleus are observed, they are single and in more mature stages.

This is in contrast to disease states characterized by a transition to the bone marrow, in which erythrocytes with a nucleus can be found in greater numbers and appear immature.

Adjustment of reticulocyte

When chlorosis develops, the bone marrow will respond with increased reticulocytes, maintaining hemoglobin levels. Therefore, an absence of an increased number of cells reflects the inability of the bone marrow to compensate for chlorosis. Laboratory findings show the number of these cells as a percentage of the total number of erythrocytes. So, adjustment of reticulocyte count according to the degree of chlorosis is below:

Reticulocyte\% \; adjusted = reticulocyte\% \; \times\frac {Hct} {45}

Red cells circulate in the blood one day before they become mature erythrocytes. However, if released from the bone marrow prematurely, they can circulate in the blood for 2-3 days. This is usually seen in severe chlorosis. Therefore, each reticulocyte should be present for only one day, and in cases where cells circulate in the peripheral blood for days, a correction factor is used. This correction factor is known as the reticulocyte production index (RPI) and is calculated as follows:

RPI = \frac {Reticulocyte\% \; adjusted} {correction \; factor}
Patients Hct (%)Correction factor

RPI value <2 indicates an inadequate bone marrow response, while an RPI > 2 indicates that the bone marrow response is appropriate for the degree of anemia.

For instance, the normal values are:

  • Adults: 0.5 to 1.5%,
  • Newborns: 3 to 6%.

So with chlorosis, red cells would be expected to be high because the response is to increase bone marrow production. In this situation, a low or even normal reticulocyte count may signify that the bone marrow is not functioning as it should.

Absolute Reticulocyte Count Formula

The Reticulocyte Count formula is:

ARC = Reticulocytes \times \frac {Hematocrit} {Normal \; Hematocrit}

Hematocrit is the percentage concentration of red cells in the blood (erythrocytes). The normal value is around 45% for men and 40% for women.

Absolute Reticulocyte Count – Interpretation

The percentage of reticulocytes among red cells and one’s hematocrit (Hct) is used for determination. Normal hematocrit is a default value of 45%, but you can change it to the desired value in advanced mode. The calculated absolute reticulocyte count is expressed in cells per microliter (cells/μL)

Absolute Reticulocyte Count Calculator – How to Use?

So, in our calculator you need to enter the predicted patterns of hematocrit values in the patient. Also, you should pay attention to values in men and women. We then enter reticulocyte values which we determine based on hematocrit values. The calculator calculates the values immediately, expressed in cells/μL.

Absolute Reticulocyte Count Calculator – Example

For example, we have a patient whose hematocrit value is 39%, and the reticulocyte count is 1%. So, the absolute reticulocyte calculator calculates that the value of the absolute number  is 0.867 cells/μL. This means that based on the established values, it is a normal value for an adult, in this case, a woman.


What is a reticulocyte count?

Red blood cells that are still developing. Approximately two days after they form, they develop into mature red  cells. These red  cells carry oxygen from the lungs to every cell in your body. A reticulocyte count measures the number of red cells in the blood. If the number is too high or too low, it can mean a serious health problem, including anemia and bone marrow, liver, and kidney disorders.

How to calculate absolute reticulocyte count?

To determine the absolute number, it is necessary to know the following medical values: patient’s value of hematocrit and reticulocyte values.

What is a normal absolute reticulocyte count?

Normal clinical values of the absolute number are:
Adults: 0.5 to 1.5%
Newborns: 3 to 6%

What is the difference between reticulocyte count and absolute reticulocyte count?

A reticulocyte count measures immature red cells (“adolescent” red blood cells) that have recently been released from the bone marrow into the circulation and are usually about 1% in people who have a normal red cell count. The absolute number of red cells measures the value of reticulocytes and one’s hematocrit.

What does a low absolute reticulocyte count mean?

Anemia with normal or low reticulocyte counts indicates decreased erythrocyte production in the bone marrow. These are two large groups: anemia due to weakness and bone marrow disease or anemia due to maturation disorders (vitamin B12, folic acid, or iron deficiency).

What happens if the reticulocyte count is high?

Anemia with increased reticulocyte counts indicates hemolytic anemia or anemia due to blood loss. The normal lifespan of erythrocytes is about 120 days. In the case of hemolytic anemia, their lifespan is reduced to 20-40 days, in moderate hemolysis, or 5-20 days in severe hemolytic anemia.