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Red Blood Cell Count (Automated Hematology)

Published: August 9, 2026Updated: August 17, 2026

This test measures the number of red blood cells (RBCs) in your blood, which helps assess your overall blood health and detect conditions like anemia or polycythemia.

Quick summary

["RBC count helps diagnose and monitor blood-related disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
34525-6
Short code
rstRBC Bld Ql Auto
Synonyms
rstRBC Bld Ql Auto
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
automated-count
CPT
85041
SNOMED
900000000000003001
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?

Doctors may order this test to check for anemia (low RBCs), polycythemia (high RBCs), or other blood conditions. It’s also used in routine health checks, before surgeries, or when symptoms like fatigue, pale skin, or dizziness appear.

What to Expect During the Test

A small blood sample is taken from a vein in your arm using a needle. The blood is then analyzed automatically in a lab to count your RBCs. This process usually takes a few minutes and may cause a slight pinch or discomfort.

Factors That Can Affect Results

Several factors, such as dehydration, recent blood loss, or certain medications, can influence RBC counts. Pregnancy, high altitudes, or chronic diseases may also play a role. Your doctor will consider these when interpreting the results.

Common Conditions Linked to RBC Counts

Low RBC counts (anemia) may be caused by iron deficiency, blood loss, or kidney problems, while high RBC counts (polycythemia) can result from conditions like dehydration, lung disease, or certain cancers. Your doctor will work with your symptoms and other test results to diagnose the cause.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

RBC Count

Frequently asked questions

How long does it take to get my RBC count results back?
Results are typically available within 1 to 3 business days, depending on your lab. Your doctor will contact you if additional follow-up is needed.
Can I eat or drink anything before this test?
No special preparation is usually required. However, avoid alcohol for 24 hours before testing if your doctor advises it, as it may affect blood composition.
Will I feel any pain during the blood draw?
Most people experience only mild discomfort or a slight sting during the blood draw. Some may feel a pinch, but the procedure is quick and rarely causes significant pain.
  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 17, 2026. · Read our editorial policy