What it measures
Reticulocytes are young red blood cells newly released from the bone marrow. The count shows how fast the marrow is making new red cells. It is usually measured by the same analyser that runs the full blood count.
Why people test it
- Used in anaemia to tell whether the marrow is making too few red cells or they are being lost faster.
- Checked after blood loss, or when red cells are breaking down early (haemolysis).
- Repeated after iron, B12 or folate are started, to see whether the count rises.
- Tracked by some endurance athletes around altitude training, when red cell production rises.
Typical range
Ranges vary by lab and method, and results may be given as a count, a percentage of red cells, or both. Your report shows the lab's own range.
Finger-prick or vein?
A vein sample is usually advised. Blood from a finger prick can clot or break up (haemolyse) in the tube, which upsets blood-count results.