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Complete Blood Count (CBC) with Differential and Platelet Count

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

This test measures three key components of your blood: white blood cells (to help fight infections), red blood cells (to carry oxygen), and platelets (to aid in blood clotting).

Quick summary

["A CBC helps doctors assess overall health, detect infections, anemia, or bleeding disorders."]

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

Key facts at a glance

LOINC
48705-8
Short code
WBC+Platelets Bld
Synonyms
WBC+Platelets Bld
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85004
SNOMED
900000000000003002
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 This Test Is Done

Doctors order a CBC to monitor general health, diagnose conditions like infections, anemia, or blood disorders, or check for signs of disease progression. It’s also used before surgeries, during chemotherapy, or if you have symptoms like fatigue, bruising, or frequent infections.

What to Expect Before the Test

You won’t need special preparation. The test involves a simple blood draw from a vein in your arm. If you’re on blood thinners, tell your doctor beforehand.

What the Results Mean

Results show counts for white blood cells (including subtypes like neutrophils, lymphocytes, etc.), red blood cells, and platelets. Abnormal counts may signal infections, bleeding risks, or other health issues.

Common Conditions Linked to CBC Results

Low white blood cell counts (leukopenia) may indicate immune problems or infections. High platelet counts (thrombocytosis) could signal bleeding disorders or inflammation. Low red blood cells (anemia) may point to iron deficiency or chronic disease.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CBC with Platelet Count

Frequently asked questions

What does a ‘complete blood count’ measure?
It measures three main components: white blood cells (including their subtypes), red blood cells, and platelets. These counts help assess immune function, oxygen-carrying capacity, and blood clotting ability.
How often should I get a CBC?
Frequency depends on your health. Doctors may recommend regular CBCs if you have chronic conditions (e.g., diabetes, kidney disease), undergo treatments (e.g., chemotherapy), or show symptoms like fatigue or bruising.
Can diet affect CBC results?
Yes—diet can influence red blood cell counts (e.g., iron-rich foods affect anemia risk) and platelet function (e.g., vitamin K intake supports clotting). Avoid extreme dietary changes before testing.
  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