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Reticulocyte Count (Manual Count of Immature Red Blood Cells)

Published: August 9, 2026Updated: August 16, 2026

This test measures the number of reticulocytes in your blood. Reticulocytes are young red blood cells that are still producing ribonucleic acid (RNA) and appear slightly larger and bluer under a microscope.

Quick summary

["Reticulocytes help your doctor assess how well your bone marrow is producing new red blood cells."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
66146-2
Short code
Retics # Fetus Manual
Synonyms
Retics # Fetus Manual
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order a reticulocyte count to check for conditions affecting red blood cell production, such as anemia, bone marrow disorders, or blood loss. It can also help determine if your body is responding to treatments like iron supplements or chemotherapy.

What to Expect Before the Test

No special preparation is needed for this test. A simple blood draw is performed in a clinic or lab. The blood sample is examined under a microscope to count the reticulocytes manually.

What the Results Mean

The results show the proportion of reticulocytes relative to total red blood cells. High reticulocyte counts may indicate increased red blood cell production, while low counts may suggest poor bone marrow function or blood loss.

Common Conditions Affecting Reticulocyte Counts

High reticulocyte counts can occur in conditions like hemolytic anemia (where red blood cells are destroyed too quickly) or after blood loss. Low reticulocyte counts may signal anemia due to iron deficiency, vitamin deficiencies, or bone marrow diseases.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Reticulocyte Count

Frequently asked questions

How often will I need this test?
This test is often done as part of a routine blood panel or when symptoms like fatigue, pale skin, or shortness of breath appear. Your doctor may repeat it if you’re undergoing treatment for anemia or other blood-related conditions.
Can I eat or drink anything before the test?
No special diet or fasting is required. However, inform your doctor about any medications you’re taking, as some may affect blood counts.
What does a normal reticulocyte count mean for my health?
A normal reticulocyte count doesn’t necessarily mean you’re healthy, but it suggests your bone marrow is producing red blood cells appropriately. Your doctor will interpret results in the context of your overall health and symptoms.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy