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Factor Xa Inhibitor (Antithrombin Complex) Level

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

This test measures how well your blood naturally prevents clots from forming by checking levels of Factor Xa inhibitors, including antithrombin and other proteins that slow blood clotting.

Quick summary

["Helps assess your risk for abnormal clotting or bleeding based on natural anticoagulant activity."]

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

Key facts at a glance

LOINC
96459-3
Short code
Fact IX Act + Inhib Pnl PPP
Synonyms
Fact IX Act + Inhib Pnl 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 This Test Might Be Ordered

Your doctor may recommend this test if you have a history of blood clots, bleeding disorders, or are taking anticoagulant medications. It can also help monitor treatment effectiveness or diagnose clotting-related conditions.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw from a vein in your arm. If you’re on blood thinners, inform your healthcare provider beforehand to ensure safety.

What the Test Results Mean

Results show whether your blood’s natural clotting inhibitors are functioning as expected. Abnormal levels may indicate bleeding risks or clotting disorders, depending on your clinical context.

Common Causes of Abnormal Results

Low levels may suggest inherited or acquired clotting disorders, while high levels could be due to medications or rare genetic conditions affecting anticoagulant proteins.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test helps diagnose bleeding disorders (e.g., hemophilia variants) or evaluate anticoagulant therapy (e.g., for patients on heparin or warfarin). It’s particularly useful for monitoring patients with inherited deficiencies in Factor Xa inhibitors.

Short name

Factor Xa Inhibition Test

Frequently asked questions

What does a ‘positive’ or ‘negative’ result mean?
A ‘positive’ result typically means your blood has sufficient natural inhibitors to prevent clotting, while a ‘negative’ or altered result may require further evaluation by your doctor.
How long does it take to get results?
Results are usually available within 1–3 business days, depending on lab processing times. Your doctor will discuss findings with you during your follow-up visit.
Can I eat or drink before this test?
You can eat and drink normally before the test unless instructed otherwise by your healthcare provider. Avoid alcohol or medications that may affect blood clotting for 24 hours prior.
  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