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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 in your blood, which plays a role in blood clotting. It helps assess bleeding disorders or evaluate treatment responses in conditions like hemophilia.

Quick summary

["This test helps diagnose or monitor bleeding risks linked to inherited or acquired Factor X inhibitor conditions."]

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

Key facts at a glance

LOINC
30086-3
Short code
Fact IX Inhib PPP Ql
Synonyms
Fact IX Inhib PPP Ql
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 Matters

Factor X is a key protein in the blood clotting process. If your body produces an inhibitor that blocks its activity, it can lead to prolonged bleeding or excessive clotting. This test checks how effectively your blood can form clots under certain 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 anticoagulants, inform your healthcare provider before the test.

How the Test Works

Blood is drawn and tested for its ability to clot in the presence of a specific activator. The inhibitor’s presence slows or prevents clotting, which is measured to determine activity levels.

Common Uses

This test is primarily used to diagnose Factor X inhibitor disorders (e.g., hemophilia A with inhibitor) or monitor treatment effectiveness in patients receiving replacement therapies.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Factor X Inhibitor

Frequently asked questions

What does a high or low result mean?
A high result suggests the presence of an inhibitor that interferes with normal clotting, which may require specialized treatment. A low or normal result indicates typical clotting function.
Can diet or medications affect this test?
Certain medications (like anticoagulants) or dietary supplements may influence blood clotting indirectly. Always discuss your medications with your healthcare provider before testing.
How often should this test be done?
Frequency depends on your condition. Regular monitoring may be needed if you have a Factor X inhibitor disorder or are on replacement therapy to track treatment effectiveness.
  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