The Reticulocyte Count test contains 1 test with 2 biomarkers.
Description: Reticulocytes are red blood cells that are not fully developed yet. The reticulocyte test is used to measure the amount of underdeveloped 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
Average Processing Time: 2 to 3 days
When is a Reticulocyte Count test ordered?
A reticulocyte count may be requested in the following situations:
- A low RBC count, as well as a low hemoglobin and hematocrit, are found on a complete blood count.
- A doctor wants to check the function of the bone marrow.
- Paleness, loss of energy, exhaustion, weakness, shortness of breath, and/or blood in the stool are signs and symptoms of anemia or persistent bleeding.
- A disorder known to impact RBC production, such as iron deficiency anemia, vitamin B12 or folate deficiency, or renal illness, has been recognized and is being treated.
- A person is receiving radiation or chemotherapy.
- A bone marrow transplant has been performed.
When a person has an increased quantity of RBCs and an elevated hemoglobin and hematocrit, a blood test is performed to evaluate the degree and pace of RBC overproduction.
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:
- Complete Blood Count (CBC)
- Red Blood Cell Count
- Blood Smear
- Vitamin B12
- Iron Total
- Iron and Total Iron Binding Capacity
Conditions where a Reticulocyte Count test is recommended:
- Bone Marrow Disorders
- Myeloproliferative Neoplasms
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
- 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.
- 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
We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.