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Platelet Blood Count

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

This test measures the number of platelets in your blood, which are tiny cells that help prevent bleeding and promote clotting.

Quick summary

["Platelets help stop bleeding and support blood clotting; low or high levels may signal health concerns."]

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

Key facts at a glance

LOINC
11125-2
Short code
Platelet Bld
Synonyms
Platelet Bld
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

Why This Test Matters

Platelets are essential for normal blood clotting. Your doctor may order this test if you have symptoms like easy bruising, prolonged bleeding, excessive bleeding after injury, or unexplained fatigue. It may also be checked before surgeries, during chemotherapy, or if you have conditions like anemia or bleeding disorders.

What to Expect Before the Test

No special preparation is needed. You may eat and drink normally before the test. A small needle will be used to draw blood from a vein, usually in your arm. The process is quick and usually painless.

What the Results Mean

Results are typically reported as the number of platelets per microliter (µL) of blood. A lower than normal platelet count (thrombocytopenia) or higher than normal count (thrombocytosis) may indicate underlying health issues.

Common Conditions Affecting Platelets

Low platelet counts can be caused by medications, certain diseases (like leukemia or liver disease), infections, or autoimmune conditions. High platelet counts may result from infections, inflammation, or certain cancers.

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.

Clinical Significance

Short name

Platelet Count

Frequently asked questions

What causes low platelet counts?
Low platelet counts can be due to several factors, including medications that suppress platelet production, conditions that destroy platelets (like autoimmune disorders), or problems with platelet production in the bone marrow. It can also be caused by blood loss or certain infections.
What are the symptoms of abnormal platelet counts?
Symptoms of low platelet counts may include easy bruising, prolonged bleeding from cuts, nosebleeds, or petichiae (small red spots under the skin). High platelet counts may cause fatigue, dizziness, or an increased risk of blood clots.
Can platelet counts change over time?
Yes, platelet counts can fluctuate due to various factors such as illness, medications, stress, or certain foods. Regular monitoring may be necessary if you have a condition that affects platelet levels.
  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