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Factor X Inhibitor Activity (Plasma)

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

This test measures the activity of a protein that naturally inhibits Factor X, a clotting factor in your blood. It helps assess bleeding risks or diagnose bleeding disorders.

Quick summary

["This test evaluates blood clotting regulation by checking inhibitor levels that may affect bleeding tendencies."]

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

Key facts at a glance

LOINC
3185-6
Short code
Fact IX Inhib PPP-aCnc
Synonyms
Fact IX Inhib PPP-aCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
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 healthcare provider may recommend this test if you have symptoms of bleeding (e.g., excessive bruising, nosebleeds, or prolonged bleeding after surgery) or if you have a suspected inherited bleeding disorder. It may also be used in research or specialized clinical scenarios.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, typically drawn from a vein in your arm. Avoid strenuous activity or aspirin/ibuprofen 48 hours before testing if instructed.

What the Test Results Mean

Results are qualitative (present/absent) and indicate whether Factor X inhibitor is detected. High levels may suggest a bleeding disorder requiring further evaluation.

Common Conditions Linked to This Test

This test is primarily used to diagnose or monitor Factor X inhibitor-related bleeding disorders, such as acquired or congenital hemophilia variants.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: Elevated Factor X inhibitor levels can interfere with blood clotting, increasing bleeding risk. Low or absent levels are typical in healthy individuals without inhibitors.

Short name

Factor X Inhibitor

Frequently asked questions

Will I need to fast before this test?
No fasting is required unless your provider specifies otherwise. Blood tests like this are usually done on an empty stomach for accuracy, but ask your provider if unsure.
How long will I have to wait for my results?
Results are typically available within 1–3 business days, depending on lab processing. Follow-up with your provider to discuss findings.
Can I take any medications before this test?
Avoid blood-thinning medications (e.g., aspirin, warfarin) or NSAIDs 48 hours prior unless cleared by your provider. Always confirm with your healthcare team.
  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