Reticulocyte Count

The Reticulocyte Count test contains 1 test with 2 biomarkers.

Brief Description: The reticulocyte count test is a laboratory test used to measure the number of reticulocytes in the blood. Reticulocytes are immature red blood cells that are released into the bloodstream from the bone marrow. This test provides valuable information about the production and maturation of red blood cells.

Also Known As: Retic Count Reticulocyte Percent Test, Reticulocyte Index Test, Corrected Reticulocyte Test, Reticulocyte Production Index Test, RPI Test

Collection Method: Blood Draw

Specimen Type: Whole Blood

Test Preparation: No preparation required

When is a Reticulocyte Count test ordered?

A reticulocyte count test may be ordered in the following situations:

1. Evaluation of Anemia: When a patient presents with signs and symptoms of anemia, such as fatigue, weakness, and shortness of breath, a reticulocyte count test may be ordered. It helps determine whether the bone marrow is responding appropriately by producing an increased number of reticulocytes in response to low red blood cell levels.

2. Monitoring Bone Marrow Function: The test may be used to monitor bone marrow function in individuals undergoing treatment for conditions that affect red blood cell production, such as chemotherapy, radiation therapy, or bone marrow disorders. It helps assess the effectiveness of treatment and the recovery of bone marrow function.

3. Diagnosis of Hemolytic Anemia: Reticulocyte count is often used in the evaluation of hemolytic anemia, a condition where red blood cells are destroyed prematurely. It helps determine if the bone marrow is compensating for the increased red blood cell destruction by producing an increased number of reticulocytes.

What does a Reticulocyte Count blood test check for?

Reticulocytes are young red blood cells that have just been created. The number and/or percentage of reticulocytes in the blood is determined by a reticulocyte test, which is a reflection of recent bone marrow function or activity.

Red blood cells are made in the bone marrow, where blood-forming stem cells differentiate and grow into reticulocytes, which then mature into mature RBCs. When compared to mature RBCs, reticulocytes have a volume of about 24 percent more. Although adult RBCs do not have a nucleus like most other cells in the body, reticulocytes still contain some genetic material. Reticulocytes lose the last traces of RNA as they mature, and most of them are fully matured within a day of being released from the bone marrow into the bloodstream. The reticulocyte count or percentage is an excellent measure of a person's ability to manufacture enough red blood cells in their bone marrow.

RBCs last around 120 days in circulation, and the bone marrow must constantly manufacture new RBCs to replace those that have aged and degraded or have been lost due to hemorrhage. Normally, a steady number of RBCs is maintained in the blood by replacing deteriorated or lost RBCs on a regular basis.

A range of diseases and conditions, including those that cause severe bleeding, can impair the creation of new RBCs and/or their survival. These situations can cause an increase or decrease in the number of RBCs, as well as a change in the reticulocyte count.

Reticulocyte % higher than normal: Anemia is caused by a lack of RBCs in the blood due to acute or chronic bleeding or enhanced RBC breakdown (hemolysis). The body adjusts for this loss or responds to deficiency anemia treatment by increasing RBC production and releasing RBCs into the bloodstream before they mature. When this happens, the number and percentage of reticulocytes in the blood grows until the bone marrow's production capacity is reached or until a sufficient number of RBCs replaces those that were lost.

A lower-than-normal percentage of reticulocytes: When the bone marrow isn't working properly, RBC production can suffer. A bone marrow condition, such as aplastic anemia, can cause this. Other causes that might cause decreased production include liver cirrhosis, kidney disease, cancer treatments such as radiation or chemotherapy, a low amount of the hormone erythropoietin, or dietary shortages such as iron, vitamin B12, or folate. As old RBCs are eliminated from the blood but not entirely replaced, there are fewer RBCs in circulation, poorer hemoglobin and oxygen-carrying capacity, a lower hematocrit, and a lower number of reticulocytes.

Due to excessive RBC production by the bone marrow, both the reticulocyte and RBC counts might occasionally rise. This could be caused by increased erythropoietin production, diseases that cause chronic RBC overproduction (polycythemia vera), or cigarette smoking.

Some medications can increase or reduce the number of reticulocytes in the body.

Lab tests often ordered with a Reticulocyte Count test:

When a Reticulocyte Count is ordered, it's often part of a broader assessment of hematologic health. Here are some tests commonly ordered alongside it:

1. Complete Blood Count (CBC):

   • Purpose: Provides a broad picture of overall blood health, including red and white blood cells, hemoglobin, hematocrit, and platelets.
   • Why Is It Ordered: To evaluate overall blood cell health and quantity, helping to diagnose conditions like anemia, infection, and inflammation.

2. Iron Studies:

   • Purpose: To evaluate body iron stores and iron utilization.
   • Why Is It Ordered: To diagnose iron deficiency anemia or iron overload conditions like hemochromatosis, which can affect red blood cell production.

3. Vitamin B12 and Folate Tests:

   • Purpose: To measure levels of these essential vitamins.
   • Why Is It Ordered: To identify deficiencies that can lead to types of anemia, such as megaloblastic anemia, where red blood cells are abnormally large.

4. Erythropoietin (EPO) Level:

   • Purpose: To measure the amount of EPO, a hormone that stimulates red blood cell production.
   • Why Is It Ordered: To evaluate the body’s response to anemia and help diagnose conditions affecting red blood cell production.

5. Kidney Function Test:

   • Purpose: To evaluate kidney function.
   • Why Is It Ordered: Kidney disease can affect EPO production and red blood cell production.

6. Liver Function Test:

   • Purpose: To assess liver health.
   • Why Is It Ordered: Liver diseases can impact overall health, including the metabolism of nutrients essential for blood cell production.

These tests, when ordered alongside a Reticulocyte Count, provide a comprehensive view of an individual's hematologic status. They are crucial in diagnosing the cause of anemia, assessing bone marrow function, and monitoring the response to treatments like iron supplementation, vitamin therapy, or other interventions. The specific combination of tests will depend on the individual’s symptoms, medical history, and initial test results.

Conditions where a Reticulocyte Count test is recommended:

A reticulocyte count test may be required in the following conditions or situations:

1. Anemia: The test is commonly ordered when there is a suspicion of anemia to determine if the bone marrow is producing an adequate number of reticulocytes in response to low red blood cell levels. It helps differentiate between different types of anemia and guide further evaluation and treatment.

2. Bone Marrow Disorders: Individuals with suspected bone marrow disorders, such as aplastic anemia, myelodysplastic syndrome, or leukemia, may undergo a reticulocyte count test to assess bone marrow function and evaluate the production of red blood cells.

3. Monitoring Treatment: Patients receiving treatments that may affect red blood cell production, such as chemotherapy or radiation therapy, may have regular reticulocyte count tests to monitor the recovery of bone marrow function and assess the response to treatment.

How does my health care provider use a Reticulocyte Count test?

A reticulocyte test is used to assess the number and/or percentage of reticulocytes in the blood to aid in the diagnosis of red blood cell abnormalities such as anemia and bone marrow illnesses. Reticulocytes are young red blood cells that have just been created. Before being released into the circulation, they develop and mature in the bone marrow.

The reticulocyte test can be used in the following situations:

• To help determine the reason of aberrant results on a complete blood count, RBC count, hemoglobin, or hematocrit.
• To see if the bone marrow is appropriately functioning and reacting to the body's need for red blood cells.
• To aid in the detection and differentiation of various kinds of anemia
• To track how well people are responding to treatments, such as those for iron deficiency anemia.
• To track the activity of the bone marrow after therapies like chemotherapy.
• To keep track of how well you're doing after a bone marrow transplant.

A reticulocyte count is usually done using an automated device and can be done in conjunction with a complete blood count, which includes an RBC count, hemoglobin, and hematocrit. It is possible to report either an absolute number of reticulocytes or a percentage of reticulocytes. The number of reticulocytes is compared to the total number of red blood cells as a percentage:

[ Number of Reticulocytes / Total Red Blood Cells ] X 100 = Reticulocyte Percentage

Several more tests, in addition to a reticulocyte count, can be done to further screen someone for a disorder that affects RBC production. Here are a few examples:

• Iron testing
• Haptoglobin
• G6PD
• Erythropoietin
• Vitamin B12 and Folate

Following up on abnormal results from early tests, a bone marrow aspiration and biopsy may be performed. This is an invasive operation that is not performed on everyone. If necessary, it can, however, supply extra information.

What do my reticulocyte count test results mean?

The results must be carefully evaluated in conjunction with the results of other tests, such as a red blood cell count, hemoglobin, hematocrit, or a complete blood count. The reticulocyte count, in general, reflects recent bone marrow activity. The results could reveal whether a disease or condition is present that is causing an elevated need for new RBCs, as well as whether the bone marrow is capable of meeting that demand. Overproduction of RBCs may be detected in some cases.

When anemia is present and the bone marrow responds adequately to the demand for more RBCs, the bone marrow will create more and allow for the early release of more immature RBCs, resulting in an increase in the number of reticulocytes in the blood.

A high reticulocyte count along with low RBCs, hemoglobin, and hematocrit may indicate the following conditions:

• When a person bleeds, the number of reticulocytes increases after a few days to make up for the loss of red blood cells. If someone has chronic blood loss, the marrow will try to keep up with the need for new RBCs by increasing the number of reticulocytes.
• Anemia is caused by an increase in the breakdown of RBCs in hemolytic anemia. To compensate, the bone marrow boosts RBC production, resulting in a high reticulocyte count.
• Hemolytic illness of the newborn: Similar to hemolytic anemia, this syndrome causes an increase in RBC destruction.

For example, a low reticulocyte count with low hemoglobin, low red blood cells, and low hematocrit can be detected when:

• Anemia due to a lack of iron
• Folic acid deficiency or pernicious anemia
• Aplastic anemia is a kind of anemia that occurs when the
• Radiation therapy is a type of treatment that uses a
• Infection or malignancy can induce bone marrow failure.
• A low level of erythropoietin can be caused by severe kidney disease.
• Alcoholism
• Endocrine illness

When a person has anemia, the percentage of reticulocytes in their blood may appear to be higher than the total number of RBCs. A calculation known as a corrected reticulocyte count or reticulocyte index may be reported to get a more accurate estimate of bone marrow function. When a person's hematocrit is compared to a normal hematocrit reading, the RI is computed. The reticulocyte production index and an immature reticulocyte fraction are two more estimates that may be presented. The IRF was once known as the reticulocyte maturity index, but it is currently the most widely used phrase to describe the younger percentage of reticulocytes.

The existence of a disease or condition is indicated by the reticulocyte test, however it is not specifically diagnostic of any disease. It's a warning that more research is needed, as well as a method for monitoring therapy effectiveness.

When reticulocyte numbers increase after chemotherapy, a bone marrow transplant, or treatment for an iron, vitamin B12, or folate shortage, bone marrow RBC production is on the mend.

A high reticulocyte count can indicate an overproduction of RBCs in people who do not have anemia or have a high RBC count. This can be caused by a variety of factors, including:

• Polycythemia vera
• Excess erythropoietin-producing tumor

Most Common Questions About the Reticulocyte Count test:

Understanding the Reticulocyte Count Test

What is the Reticulocyte Count test?

The Reticulocyte Count test is a type of blood test that measures the number of reticulocytes, or immature red blood cells (RBCs), in a blood sample. Reticulocytes are the last stage of development before becoming mature RBCs.

Why is the Reticulocyte Count test important?

This test helps determine if the bone marrow is producing red blood cells at an adequate rate. It can be used to help diagnose and monitor conditions such as anemia, and evaluate how the body is responding to treatments for conditions affecting red blood cell production.

Interpreting Reticulocyte Count Results

What does a high Reticulocyte Count indicate?

A high Reticulocyte Count often indicates an increased red blood cell production. This can occur in conditions where red blood cells are being lost or destroyed at an accelerated rate, such as hemolytic anemia or after a significant bleeding event.

What does a low Reticulocyte Count mean?

A low Reticulocyte Count can suggest that the bone marrow is not producing red blood cells at an adequate rate. This could be due to conditions such as iron deficiency anemia, vitamin B12 or folate deficiency, or bone marrow disorders.

How are Reticulocyte Count test results interpreted?

The results are typically given as a percentage of the total number of red blood cells. A normal range for adults is generally between about 0.5% and 2.5% of the total red blood cell count, although this can vary depending on the laboratory and the individual.

Reticulocyte Count and Specific Conditions

How is the Reticulocyte Count test used in the diagnosis of anemia?

The Reticulocyte Count test can help determine whether anemia is due to decreased production of red blood cells (low reticulocyte count) or increased destruction or loss of red blood cells (high reticulocyte count).

Can the Reticulocyte Count test help in the diagnosis of bone marrow disorders?

Yes, a low Reticulocyte Count could suggest a problem with the bone marrow's ability to produce red blood cells, which could be due to a bone marrow disorder.

How can the Reticulocyte Count test help in evaluating the body's response to treatment for anemia?

An increase in the reticulocyte count after treatment for anemia would generally indicate that the treatment is effective and the bone marrow is responding by producing more red blood cells.

Can the Reticulocyte Count test help diagnose conditions like hemolytic anemia?

Yes, in conditions like hemolytic anemia where red blood cells are destroyed prematurely, the bone marrow compensates by producing more red blood cells, leading to a high Reticulocyte Count.

General Queries about the Test

Can the Reticulocyte Count test be used to monitor kidney disease?

Reticulocyte Count may indirectly reflect the status of kidney disease. In advanced kidney disease, there's often decreased production of erythropoietin (a hormone that stimulates red blood cell production), leading to a low Reticulocyte Count.

Why might the Reticulocyte Count test be ordered alongside a Complete Blood Count (CBC)?

A CBC provides information about the numbers and types of cells in the blood, while the Reticulocyte Count specifically measures the production of new red blood cells. These tests together can provide a more comprehensive view of a person's hematological health.

Why would a doctor order a Reticulocyte Count test?

A doctor might order this test if a person has symptoms of anemia (like fatigue, weakness, pallor), or to monitor the body's response to treatment for conditions affecting red blood cell production.

How often should the Reticulocyte Count test be done?

The frequency of the test depends on the clinical context. It might be done more frequently when monitoring response to treatment for conditions like anemia.

Can the Reticulocyte Count test predict the likelihood of developing anemia?

The Reticulocyte Count test doesn't predict the likelihood of developing anemia. However, abnormal results could indicate a problem with red blood cell production that might lead to anemia.

Can certain factors affect the accuracy of the Reticulocyte Count test?

Yes, factors like recent blood transfusion or erythropoietin therapy can influence the results.

How effective is the Reticulocyte Count test in diagnosing anemia?

While the test itself doesn't diagnose anemia, it can provide valuable information about the cause of anemia and how the body is responding to it.

Can the Reticulocyte Count test replace other tests for diagnosing anemia?

No, the Reticulocyte Count test is typically used in conjunction with other tests like the CBC and iron studies to diagnose anemia.

Why does the Reticulocyte Count test focus on immature red blood cells?

Reticulocytes are the last stage before red blood cells mature. Measuring them gives information about the rate of red blood cell production in the bone marrow.

Can the Reticulocyte Count test be used in people who've recently received a blood transfusion?

Yes, but it's important to note that a recent blood transfusion may affect the results of the test as the transfused blood will also contain reticulocytes.

What could cause a false positive or negative in the Reticulocyte Count test?

The count might be falsely elevated in conditions with increased red blood cell turnover. On the other hand, recent blood loss or transfusion, or iron, B12, or folate deficiency could lead to falsely low counts.

What's the significance of the absolute reticulocyte count?

The absolute reticulocyte count gives a more precise estimate of new red blood cell production, factoring in both the percentage of reticulocytes and the total red blood cell count.

Can the Reticulocyte Count test differentiate between different types of anemia?

The test can help differentiate between anemias caused by decreased red blood cell production versus those caused by increased red blood cell destruction or loss.

Can you have a normal Reticulocyte Count test and still have a medical condition?

Yes, it's possible to have a normal reticulocyte count and still have a medical condition. For example, a person with early stage kidney disease might have a normal reticulocyte count.

Can the Reticulocyte Count test detect bone marrow diseases like leukemia or lymphoma?

While the test can suggest a problem with bone marrow function, it cannot directly detect diseases like leukemia or lymphoma.

Is the Reticulocyte Count test used in the diagnosis or management of polycythemia vera?

Yes, the Reticulocyte Count test can be used in the management of polycythemia vera. A high reticulocyte count can be a sign of active disease.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.