What is the Reticulocyte Count test?

The Reticulocyte Count blood test measures the number and proportion of reticulocytes, which are immature red blood cells recently released from the bone marrow into the bloodstream. Reticulocytes typically mature into fully functional red blood cells within one to two days.

This test provides insight into how actively the bone marrow is producing red blood cells. It is especially useful when evaluating anaemia, blood loss, or bone marrow function, as it shows whether the marrow is responding appropriately to the body’s needs.

Reticulocyte count is commonly interpreted alongside Full Blood Count (FBC), haemoglobin, and iron studies.

Why do I need a test for Reticulocyte Count?

When anaemia or abnormal red blood cell levels are detected, it is important to determine whether the bone marrow is compensating by increasing red cell production. The reticulocyte count helps distinguish between reduced production and increased loss or destruction of red blood cells.

It is also useful for monitoring recovery after treatment for anaemia or following blood loss.

You may benefit from this test if you experience or have:

• Anaemia of unknown cause

• Fatigue or weakness

• Recent blood loss or bleeding

• Suspected haemolysis

• Monitoring response to iron, B12, or folate treatment

• Bone marrow disorders

• Chronic disease affecting blood production

• Post-treatment recovery assessment

Benefits of the Reticulocyte Count test

1. Assesses bone marrow activity
   Indicates how actively red blood cells are being produced.

2. Helps identify cause of anaemia
   Differentiates production failure from blood loss or destruction.

3. Monitors treatment response
   Useful after iron, B12, or folate supplementation.

4. Supports investigation of haemolysis
   Elevated counts may reflect increased red cell destruction.

5. Assesses recovery after bleeding
   Indicates marrow response following blood loss.

6. Complements Full Blood Count results
   Adds functional insight beyond haemoglobin levels.

7. Supports evaluation of marrow disorders
   Useful in suspected bone marrow suppression.

8. Simple and informative blood marker
   Requires only a routine blood sample.

Step-by-step – how we offer Reticulocyte Count testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic

• Attend your appointment

• Blood sample collected by a qualified clinician or phlebotomist

• Sample is sent to the laboratory for analysis

At-home or hotel testing (+£60)

• A qualified phlebotomist visits your home or hotel

• Blood sample collected in a comfortable, familiar setting

• No clinic visit or travel required

Both services are available UK-wide.

Your Reticulocyte Count results explained

Low reticulocyte count

Low reticulocyte levels suggest reduced red blood cell production by the bone marrow. This may occur in iron deficiency, vitamin B12 or folate deficiency, bone marrow disorders, or chronic disease.

Further investigation is often required to identify the underlying cause.

UK reference interpretation:

• Low: Below laboratory reference range

Normal reticulocyte count

Normal levels indicate appropriate red blood cell production relative to the body’s needs. In anaemia, a normal count may still suggest inadequate marrow response depending on haemoglobin levels.

Interpretation should consider overall blood results.

UK reference interpretation:

• Normal: Within laboratory reference range

High reticulocyte count

Elevated reticulocyte levels indicate increased bone marrow activity. This is commonly seen after blood loss, haemolysis, or during recovery from anaemia following treatment.

This reflects an appropriate compensatory response.

UK reference interpretation:

• High: Above laboratory reference range