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Platelet Count (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. Low or high platelet counts may indicate health concerns.

Quick summary

["Platelets help stop bleeding and support blood clotting; abnormal levels may signal bleeding disorders or clotting risks."]

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

Key facts at a glance

LOINC
54415-5
Short code
Num units trans LP platelets
Synonyms
Num units trans LP platelets
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 Is This Test Done?

Your healthcare provider may order this test to check for bleeding disorders, clotting issues, or conditions like leukemia, infection, or liver disease. It’s also used before surgeries or treatments that could affect platelet function.

What to Expect Before the Test

No special preparation is needed, but avoid aspirin or certain blood thinners 48 hours before testing if instructed. Fasted or non-fasted status doesn’t affect platelet counts.

How the Test Works

A blood sample is drawn from a vein, usually in your arm. The sample is analyzed to count platelets using automated equipment that detects their presence in whole blood.

What the Results Mean

Results are reported as the number of platelets per microliter (µL) of blood. Very low counts (thrombocytopenia) may raise concerns about bleeding risks, while very high counts (thrombocytosis) could signal clotting risks or underlying conditions.

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.

◆Associated findings1

Short name

Platelet Level

Frequently asked questions

What causes low platelet counts?
Low platelet counts can result from conditions like autoimmune disorders, infections, chemotherapy, or liver disease. Certain medications, pregnancy, or blood loss may also contribute.
What causes high platelet counts?
High platelet counts may occur due to infections, inflammation, cancer, or blood loss. Some medications or genetic factors can also increase platelet production.
Do I need to avoid certain foods before this test?
No specific diet restrictions apply, but avoid supplements like vitamin E or ginkgo biloba that may affect platelet function if you’re on blood-thinning medications.
  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