Reticulocyte Count

Bone marrow red cell production

Reticulocytes are young red blood cells that have just been released from the bone marrow, and they mature into full red cells within a day or two. Counting them shows how actively your bone marrow is making new red cells. This helps your doctor tell whether anaemia comes from the marrow not making enough cells or from the body losing or destroying them.

• To help work out what is causing anaemia
• To look for red cell breakdown (haemolysis) or recent blood loss
• To check whether the bone marrow is working properly
• To see whether treatment with iron, B12 or folate is working
• To follow recovery of the bone marrow after chemotherapy

No fasting or special steps are needed. Take your regular medicines unless your doctor says otherwise, and tell your doctor about recent blood transfusions, blood loss or treatment for anaemia, as these can change the count.

Sample

Blood sample

How it works

At home, a trained collector draws a small blood sample from a vein in your arm, which takes a few minutes. It is often tested alongside a CBC from the same visit.

Report

Within 24 hours of collection.

The report shows the reticulocyte count, often as a percentage, next to the laboratory's range. A high count usually means the bone marrow is working hard to replace red cells lost through bleeding or destroyed by haemolysis, or is responding to treatment. A low count with anaemia suggests the marrow is not making enough red cells, for example because of a shortage of iron, B12 or folate, or a marrow problem. Your doctor will interpret it with your blood count.

One test: Reticulocyte Count, from one blood sample.