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Erythrocyte Mean Corpuscular Count (Red Blood Cell Count), Mass Concentration

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

This test measures the number of red blood cells in a blood sample. Red blood cells carry oxygen from your lungs to the rest of your body.

Quick summary

["A red blood cell count helps show whether you have a normal, low, or high number of oxygen-carrying cells in your blood."]

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

Key facts at a glance

LOINC
30108-5
Short code
EME Mec-mCnt
Synonyms
EME Mec-mCnt
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

The red blood cell (RBC) count measures how many red blood cells are present in a measured volume of blood. Red blood cells contain hemoglobin, the protein that carries oxygen. The count is usually reported as part of a complete blood count (CBC).

Why It Is Ordered

Your healthcare provider may order an RBC count to help evaluate symptoms such as tiredness, weakness, or shortness of breath, or to check for anemia or other blood conditions. It is also used to monitor ongoing conditions or the effects of treatment.

How the Sample Is Collected

A small sample of blood is drawn from a vein, usually in your arm, using a needle. The sample is then analyzed in a laboratory. No special preparation is typically required unless your provider gives other instructions.

What the Results Mean

Results are compared with a reference range that varies by age, sex, and laboratory. A low count may suggest anemia or other causes of reduced red cells, while a high count may occur with certain conditions. Your provider will interpret the result along with other blood measurements and your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

RBC Count

Frequently asked questions

Does an abnormal red blood cell count always mean I have a disease?
No. Results can be affected by many factors, including hydration, altitude, and laboratory methods. An abnormal count is a clue that prompts further evaluation, not a diagnosis by itself.
Do I need to fast before this test?
Fasting is usually not required for a red blood cell count, but follow any specific instructions your provider gives, especially if other tests are being done at the same time.
Can the RBC count change over time?
Yes. Red blood cell counts can shift with illness, blood loss, nutritional status, and treatment. Your provider may repeat the test to track changes rather than relying on a single result.
  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