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Platelet Count (Peripheral Blood)

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 your body stop bleeding and protect against excessive blood loss."]

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

Key facts at a glance

LOINC
11126-0
Short code
Platelet Mar
Synonyms
Platelet Mar
Category
hematology
Sample
serum
Container
Red-top tube (SST)
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
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

Why Might This Test Be Done?

Doctors may order a platelet count to check for conditions affecting clotting, such as bleeding disorders, infections, or certain cancers. It can also be used to monitor treatments like chemotherapy or blood thinners.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or hand to draw blood. This is usually quick and painless, though some people feel slight discomfort.

What the Results Mean

Results are typically reported as the number of platelets per microliter (µL) of blood. Very high or very low counts can signal underlying health issues, but exact values depend on your medical history and symptoms.

Common Conditions Affecting Platelets

Low platelet counts (thrombocytopenia) may occur due to bone marrow disorders, medications, or autoimmune diseases. High platelet counts (thrombocytosis) can result from infections, inflammation, or certain cancers.

Reference range

Adult: 150-400 x 10^9/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Platelet counts play a critical role in diagnosing bleeding disorders, assessing risk for clotting events, and guiding treatment decisions, especially for patients on anticoagulants or undergoing surgery.

Short name

Platelet Count

Frequently asked questions

What causes a low platelet count?
Low platelet counts can be caused by conditions like leukemia, liver disease, certain medications, or autoimmune disorders where the body attacks its own platelets. Infections or pregnancy may also temporarily lower platelet levels.
How long does it take to get results?
Results are usually available within 1–2 business days, depending on your lab’s processing time. Your doctor will discuss the findings with you during your follow-up visit.
Can I eat or drink before this test?
You can eat and drink normally before this test unless your doctor instructed otherwise. Avoiding food or fluids for extended periods isn’t necessary for platelet counts.
  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