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Platelet Count (Peripheral Blood)

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

This test measures the number of platelets, a type of blood cell that helps prevent bleeding and promotes clotting.

Quick summary

["Platelets are crucial for healthy blood clotting—low levels may increase bleeding risk, while high levels may raise clot formation concerns."]

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

Key facts at a glance

LOINC
101790-4
Short code
Platelet Fn Pnl in plas
Synonyms
Platelet Fn Pnl in plas
Category
hematology
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
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
Method
coag
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 Is This Test Done?

Doctors may order a platelet count to check for bleeding disorders, infections, or conditions like leukemia, thrombocytopenia, or thrombocytosis. It’s also used before surgeries or procedures that could affect clotting.

What Does the Test Involve?

A simple blood draw from a vein (usually in your arm) is taken. The sample is sent to a lab where automated machines count the platelets and other blood cells.

What Are Common Results?

Results are reported as the number of platelets per microliter (µL) of blood. While specific ranges vary by lab, very low counts (below 150,000/µL) may signal bleeding risks, and very high counts (above 600,000/µL) may raise clot concerns.

How Is This Test Different from Other Platelet Tests?

Unlike platelet function tests (e.g., bleeding time), this test only measures platelet quantity. It doesn’t assess whether platelets work properly in stopping bleeding.

Reference range

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

Specimen: plasma

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: When Platelet Counts Matter

Short name

Platelet Count

Frequently asked questions

What causes low platelet counts (thrombocytopenia)?
Low platelet counts can result from conditions like bone marrow disorders, certain medications, autoimmune diseases, or infections. Severe cases may cause easy bruising, nosebleeds, or bleeding gums.
What causes high platelet counts (thrombocytosis)?
High platelet counts may occur due to infections, inflammation, or blood loss. Rarely, it can lead to clots, increasing the risk of heart attack or stroke.
Can diet or supplements affect platelet counts?
Some foods (like vitamin K-rich greens) or supplements (e.g., vitamin E) may influence platelet function indirectly, but they don’t typically change platelet counts on their own.
  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