What is this test?
Reticulocytes are newly produced red blood cells. Their number shows how actively the bone marrow is replacing red cells and helps distinguish different responses to anaemia or blood loss.
Why might it be ordered?
- To investigate anaemia and whether the marrow is responding appropriately.
- To monitor recovery after bleeding, treatment of a deficiency or bone-marrow suppression.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Fasting is usually unnecessary. Tell your clinician about recent bleeding, transfusion and treatment with iron, vitamin B12, folate or erythropoietin.
How should you understand the result?
The percentage can be misleading when the red-cell count is low, so clinicians may use an absolute or corrected reticulocyte count. Interpretation depends on haemoglobin and the wider CBC.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.