Reticulocyte Count
Reviewed
Also called: Reticulocyte Percent, Reticulocyte Index, Corrected Reticulocyte, Reticulocyte Production Index, RPI
A reticulocyte count measures the number of immature red blood cells (reticulocytes) in your blood. It helps check if your bone marrow is making the right amount of red blood cells.
Specimen: Blood
Why this test may be ordered
- To help diagnose specific types of anemia
- To see if treatment for anemia is working
- To check if bone marrow is producing the right amount of red blood cells
- To check bone marrow function after chemotherapy or a bone marrow transplant
- To evaluate a newborn for hemolytic disease of the newborn (HDN)
Preparation and collection
You don't need any special preparations for this test.
A health care professional will take a blood sample from a vein in your arm. For a newborn, a provider will clean the baby's heel with alcohol and poke it with a small needle to collect a few drops of blood.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly. For a newborn, there is very little risk; the baby may feel a little pinch when the heel is poked, and a small bruise may form at the site, which should go away quickly.
Understanding results
To understand the results of a reticulocyte count test, your provider will consider your symptoms, medical history, and the results of other blood tests. The following are possible result patterns.
- Higher-than-normal reticulocyte count (reticulocytosis): May indicate hemolytic anemia (red blood cells destroyed faster than bone marrow can replace them), new or ongoing bleeding (hemorrhage), or hemolytic disease of the newborn (HDN). Limitation: A higher count can also occur during pregnancy or temporarily after moving to a high altitude. Some medicines may also increase the count. Next step: Your provider will correlate with your symptoms, medical history, and other blood tests to determine the cause.
- Lower-than-normal reticulocyte count: May indicate iron deficiency anemia, pernicious anemia (B12/folate deficiency), aplastic anemia, bone marrow failure, kidney disease, or cirrhosis of the liver. Limitation: Some medicines may decrease the count. A low count does not always mean you have anemia or another health condition. Next step: Your provider will correlate with your symptoms, medical history, and other blood tests to determine the cause.
- Results must be interpreted by a healthcare professional in the context of your symptoms, medical history, and other blood tests.
- A reticulocyte count that is not normal does not always mean you have anemia or another health condition.
- Reticulocyte counts may be higher during pregnancy.
- Counts may temporarily increase after moving to a high altitude and return to normal once your body adjusts.
- Some medicines may increase or decrease your reticulocyte count.
What to do next
If you have questions about your results or your child's results, talk to your health care provider. Your provider will explain what your results mean and whether any follow-up is needed.
- What do my reticulocyte count results mean in my specific situation?
- Do I need any other tests to confirm a diagnosis?
- What are the next steps if my results are not normal?
- Could any medications I am taking affect my reticulocyte count?
- How will my treatment be adjusted based on these results?