Reticulocyte Count

A reticulocyte count (retic count) measures the number of reticulocytes in your blood. Reticulocytes are immature (still developing) red blood cells (RBCs). Your body makes reticulocytes in your bone marrow.

Then it sends them into your blood, where they mature into red blood cells within one to two days. The main job of the red blood cells is to move oxygen from your lungs to every cell in your body. Your bone marrow constantly creates new red blood cells as your body needs them.

A reticulocyte count checks to see if your bone marrow is making the right amount of red blood cells when old ones die off. If you have too few, your tissues may not get enough oxygen. If you have too many, you could be at risk for blood clots or other health concerns.

This test can check for certain health conditions or show how well a treatment is working. If the reticulocyte count is too high or too low, it can be a sign of a serious health condition, including anemia and conditions of the bone marrow, liver, and kidneys.

Why this test is done

You may need this test if:

• Other blood tests show your red blood cell levels are not normal. These tests may include a complete blood count, hemoglobin test, and/or hematocrit test.
• You are being treated with radiation or chemotherapy.
• You recently received a bone marrow transplant.

You may also need this test if you have symptoms of anemia. They include:

• Shortness of breath
• Weakness or fatigue
• Headache
• Dizziness
• Arrhythmia (a problem with the rate or rhythm of your heartbeat)

Sometimes newborn babies may have a reticulocyte count test to check for a blood disorder called hemolytic disease of the newborn (HDN). This condition may happen if your blood does not match the blood type of your unborn baby. This is known as Rh incompatibility.

It causes your immune system to attack your baby's red blood cells.

You most likely will be tested for Rh incompatibility during a routine prenatal screening. This screening helps to prevent HDN by providing early treatment.

How to prepare

You don't need any special preparations for a reticulocyte count test.

Sample type

Blood

Other names for this test

retic count, reticulocyte percent, reticulocyte index, corrected reticulocyte, reticulocyte production index, RPI