Reticulocyte Count


What is a reticulocyte count?

A reticulocyte count measures the number of immature red blood cells (reticulocytes) in your bone marrow. Healthcare providers measure reticulocytes to find out if your bone marrow is producing enough healthy red blood cells.

Your bone marrow is a red blood cell production line, constantly creating and nurturing new red blood cells to replace aging and dying red blood cells. That production line goes into high gear if you need more red blood cells than usual. Measuring reticulocytes is one of the many ways healthcare providers diagnose and monitor conditions that affect your red blood cells.

Why would someone need this test?

Your healthcare provider may order a reticulocyte count:

  • If you have anemia; they may order a reticulocyte test to diagnose the anemia’s cause.
  • To see if your bone marrow is making an adequate number of new red blood cells.
  • If you had chemotherapy for a blood disorder or had a bone marrow transplant; your healthcare provider may order reticulocyte tests to check your bone marrow function.

What is the normal range for a reticulocyte count?

Your reticulocyte count is a percentage of the total number of red blood cells in your blood sample. The normal reticulocyte count ranges between 0.5 % to 2.5% in adults and 2% to 6% in infants.

Test Details

How is this test done?

Healthcare providers take a small sample of blood from your arm. They send the sample to a laboratory for analysis. At the laboratory, technicians place the sample into a special instrument that measures all of the cells in your blood sample, including the number of reticulocytes and other important cell characteristics.

Results and Follow-Up

What does an abnormal reticulocyte count mean?

A reticulocyte counts that’s higher or lower than normal may be a sign of a blood disorder. Having an unusually high or low reticulocyte count doesn’t necessarily mean you have a specific illness. It’s important to remember this is a single test used to help diagnose potential problems. Ask your doctor to explain what your test results mean. They’re your best resource for information about your specific situation.

What medical conditions are associated with an abnormally low reticulocyte count?

A lower than normal reticulocyte count may be a sign of several conditions, including hypoproliferative anemias. Hypoproliferative anemias happen when your bone marrow can’t make enough new red blood cells. Here are examples of hypoproliferative anemias:

  • Chronic disease anemia: This is one of the most common types of anemia. It occurs in connection with several chronic illnesses such as diabetes, heart disease, lung disease, rheumatoid arthritis, chronic infections and cancer.
  • Nutritional anemias: These types of anemia happen when your bone marrow can’t make the normal number of young red blood cells because you aren’t getting enough of certain elements or vitamins. Nutritional anemias include iron-deficiency anemia, pernicious anemia (vitamin B12 anemia) or folate deficiency anemia.
  • Aplastic anemia: This is a rare blood disorder that happens when you don’t have enough stem cells in your bone marrow to create an adequate amount of blood cells.

Other conditions are:

  • Myelodysplastic syndrome: These cancers keep your stem cells from maturing into healthy red blood cells.
  • Megaloblastic anemia: This anemia happens with certain vitamin deficiencies, such as vitamin B12 or folic acid, certain medications and bone marrow diseases. The common cause is your bone marrow can’t make normal red blood cells.

What medical conditions are associated with an abnormally high reticulocyte count?

A higher-than-normal reticulocyte count may be a symptom of the following conditions:

  • Hemolytic anemia: Your bone marrow normally makes millions of blood cells per minute. Hemolytic anemia occurs when your red blood cells don’t last their normal life span (120 days). When that happens, your bone marrow makes more reticulocytes to try to make up for the loss. More reticulocytes mean an abnormally high reticulocyte count.
  • Blood loss: If you lose a lot of blood or have chronic blood loss, your bone marrow may start making more reticulocytes. Again, more reticulocytes may boost your reticulocyte count.

What questions should I ask my healthcare provider?

There are several reasons why your healthcare provider may order a reticulocyte test. You may want to know more about the test and the reasons for it. Suggested questions for your healthcare provider include:

  • Why do I need this test?
  • When will I have my test results?
  • Will I need additional blood tests?

A note from Cleveland Clinic

A reticulocyte count measures the number of immature red blood cells (reticulocytes) in your bone marrow. Healthcare providers measure reticulocytes to find out if your bone marrow is producing enough red blood cells. Your test results may show your reticulocyte count is higher or lower than normal. It can be stressful when a test result indicates something unusual is happening in your body. If that’s your situation, ask your healthcare provider to explain what your results mean. Understanding your results will help you put them into perspective so you’ll feel less anxious or stressed if your blood tests show abnormal reticulocyte levels.

Last reviewed by a Cleveland Clinic medical professional on 04/18/2022.


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