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Factor Xa Activity (Plasma)

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

This test measures the activity level of Factor Xa, a protein involved in blood clotting. It helps assess how well your blood is able to clot properly.

Quick summary

["This test evaluates your blood clotting function by checking Factor Xa activity in plasma."]

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

Key facts at a glance

LOINC
3225-0
Short code
Deprecated Fact Xia Fr PPP
Synonyms
Deprecated Fact Xia Fr PPP
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
coag
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 diagnose or monitor conditions affecting blood clotting, such as inherited or acquired bleeding disorders, or to evaluate the effectiveness of anticoagulant medications like warfarin.

What Does the Test Involve?

A blood sample is drawn from a vein, typically in your arm. The blood is then processed to separate plasma, which is tested for Factor Xa activity using a specialized laboratory method.

What Are Common Uses?

Common reasons for this test include checking for bleeding disorders, monitoring treatment for conditions like thrombophilia, or assessing the anticoagulant effect of medications that prevent blood clots.

What Might Affect Results?

Factors that could influence results include recent blood donation, certain medications (like anticoagulants or antiplatelet drugs), pregnancy, and underlying health conditions affecting blood clotting.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Factor Xa is a key enzyme in the coagulation cascade. Abnormal levels may indicate bleeding risks (low levels) or clotting risks (high levels), guiding treatment decisions for patients with bleeding disorders, thrombotic diseases, or those on anticoagulant therapy.

Short name

Factor Xa Activity

Frequently asked questions

What does a Factor Xa test tell me about my blood clotting ability?
This test helps determine how active Factor Xa is in your blood. Lower than expected levels may suggest bleeding issues, while higher levels could indicate potential clotting risks. Your results will be discussed with your healthcare provider to guide further care.
How long does it take to get results from this test?
Results are typically available within 1 to 3 business days, depending on your lab’s processing schedule. Your provider will contact you once results are ready.
Can I eat or drink anything before this test?
You can eat and drink normally before this test, as it does not require fasting. However, inform your healthcare provider about any medications you’re taking, as they may affect results.
  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