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Platelet Count (Blood)

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

This test measures the number of platelets in your blood. Platelets help your blood clot when you get injured.

Quick summary

["Platelets are crucial for healthy blood clotting and preventing excessive bleeding."]

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

Key facts at a glance

LOINC
104705-9
Short code
Platelet Bld Ql
Synonyms
Platelet Bld Ql
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
150
Ref high
400
Critical range
50 N/A – 1000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85049
SNOMED
900000000000003003
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

What Is a Platelet Count?

A platelet count is a simple blood test that checks how many platelets are in your blood. Platelets are tiny cells that play a key role in stopping bleeding by clotting blood vessels. Your doctor may order this test if you have symptoms like easy bruising, excessive bleeding, or unexplained fatigue.

Why Might You Need This Test?

Doctors may recommend a platelet count test to diagnose or monitor conditions like blood disorders, infections, or certain cancers. It can also help check if treatments are working or if you’re at risk of bleeding problems.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab, where machines automatically count the platelets. No special preparation is needed, but avoid strenuous activity 24 hours before the test.

What Do the Results Mean?

Results are reported as a count of platelets per microliter (µL) of blood. Low platelet counts (thrombocytopenia) may indicate bleeding disorders, infections, or certain medications. High counts (thrombocytosis) could signal inflammation, cancer, or other health issues.

Reference range

Adult: 150-400 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.

Platelet counts help diagnose bleeding disorders, infections, or cancers, and guide treatment decisions. Abnormal results may require further testing or adjustments to medications.

Short name

Platelet Blood Count

Frequently asked questions

What causes low platelet counts?
Low platelet counts can be caused by medications, infections, autoimmune diseases, or conditions like leukemia. Symptoms may include easy bruising or nosebleeds.
What causes high platelet counts?
High platelet counts can result from infections, inflammation, or certain cancers. Symptoms may include fatigue or unexplained bleeding.
How long does it take to get results?
Results are typically available within 1 to 2 business days, depending on your lab.
  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