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Platelet Clumping (Qualitative Blood Smear Evaluation)

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

This test examines whether your blood cells called platelets form abnormal clumps, which can affect blood flow and clotting.

Quick summary

["Assesses platelet function and potential clumping that may impact circulation or bleeding risks."]

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

Key facts at a glance

LOINC
7796-6
Short code
Platelet Clump Bld Ql Smear
Synonyms
Platelet Clump Bld Ql Smear
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
Method
microscopy-light
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 This Test Measures

A blood sample is examined under a microscope to check for unusual platelet clumps. Platelets are tiny blood cells that help stop bleeding, and clumping can indicate problems like certain blood disorders or medications affecting clotting.

Why It’s Done

Your doctor may order this test if you have symptoms like easy bruising, prolonged bleeding, or unexplained clots. It’s also used to monitor conditions like thrombocytopenia (low platelet count) or medications like heparin or aspirin that can alter platelet function.

Your blood is drawn and spread thinly on a microscope slide. A trained lab technician looks for clumps among the platelets, which appear as clusters rather than individual dots.

No preparation is needed, but inform your doctor about any medications (especially blood thinners) or recent injuries that could affect results.

The test is quick (results often available within 24 hours) and painless. You may feel a brief pinch at the venipuncture site, but no special recovery is needed.

This test is qualitative, meaning it only identifies clumping presence/absence—not exact platelet counts or specific causes.

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.

◆Associated findings1

Short name

Platelet Clumping Test

Frequently asked questions

What causes platelet clumping?
Platelet clumping can result from medications (like heparin or aspirin), certain infections, autoimmune disorders, or conditions affecting platelet production or function. It may also occur during pregnancy or after blood transfusions.
How long does it take to get results?
Results are typically available within 24 hours, but timing depends on lab workload. Follow-up with your doctor if you have concerns about symptoms or test timing.
Can I eat or drink before this test?
No special diet is required, but inform your doctor about any medications or supplements you take, as they may affect platelet function.
  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