Reticulocyte Count Blood Test

Reticulocyte Count Blood Test

What Is a Reticulocyte Count Test and Why Is It Done?

A reticulocyte (rih-TIK-yuh-low-site) count blood test measures the number of reticulocytes in the blood. Reticulocytes are immature red blood cells, or cells that aren't yet fully developed.

Red blood cells are made in the inside part of bones called bone marrow. A reticulocyte count test helps show how many new red blood cells a child's bone marrow is making.

Doctors may order a reticulocyte count to see:

• why someone has a low number of red blood cells, called anemia, or symptoms of anemia (like pale skin, tiredness, dizziness, or a fast heartbeat)
• if anemia treatment is working
• how well bone marrow is working in someone who had a bone marrow transplant or chemotherapy to treat a blood condition
• if newborns have a blood problem called hemolytic disease of the newborn, also called Rhesus (Rh) disease

Top Things to Know

• The reticulocyte count blood test checks the number of reticulocytes (immature red blood cells) in the blood.
• The test can diagnose some kinds of blood problems and show how well bone marrow is working.
• Kids might need to stop taking certain medicines or not eat or drink before the blood test.
• Your doctor can explain what it means if the reticulocyte count is high or low.

How Can I Help My Child Prepare for a Blood Test?

To help kids get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is nervous about it, work together on ways to stay calm. Deep breathing or even imagining being in a place that makes your child feel safe and relaxed can help.

What Do Reticulocyte Count Test Results Mean?

Your doctor will explain what the results of the test mean for your child. A “normal” reticulocyte count can vary based on things like age and gender. 

High Reticulocyte Count

If the reticulocyte count is high, the bone marrow is trying to make lots of red blood cells. This could be due to things like:

• hemolytic anemia: when red blood cells break down too fast, so bone marrow makes a lot more new cells
• bleeding in the body
• blood problems such as hemolytic disease of the newborn
• kidney problems
• high altitude

Low Reticulocyte Count

If the reticulocyte count is low, the bone marrow is making too few red blood cells. This could be due to things like:

• aplastic anemia, when the body stops making red blood cells because of an infection, illness, or other cause
• iron-deficiency anemia, when someone doesn't have enough iron in the diet
• deficiencies (lacks) in vitamins, like when someone doesn't get enough B12 or folic acid in the diet or the body can't absorb nutrients properly
• bone marrow, liver, or kidney problems

What Else Should I Know?

Let your doctor know if your child has had a blood transfusion or takes any medicine. This may affect the results of reticulocyte count test. If you have questions about test or what the results mean, talk to your doctor.