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Factor XIII Activity (Plasma)

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

This test measures the activity level of Factor XIII, a protein involved in blood clotting and wound healing. It helps assess bleeding disorders or conditions affecting clotting.

Quick summary

["Factor XIII supports normal blood clotting and tissue repair—abnormal levels may indicate bleeding risks or clotting issues."]

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

Key facts at a glance

LOINC
50390-4
Short code
Fact II circ inhib PPP Ql
Synonyms
Fact II circ 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
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 doctor may order this test if you have symptoms like excessive bleeding (e.g., nosebleeds, heavy menstrual periods, or bruising easily), prolonged wound healing, or a history of clotting disorders. It may also be used before surgeries or procedures requiring significant blood loss.

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-thinning medication, inform your doctor beforehand.

What the Results Mean

Results are typically reported as a percentage of normal activity. Low levels may suggest bleeding disorders, while very high levels could indicate rare clotting disorders. Your doctor will interpret results in the context of your symptoms and medical history.

Common Conditions Linked to Factor XIII Activity

Abnormal Factor XIII activity is rare but can be linked to conditions like Factor XIII deficiency (a genetic bleeding disorder) or acquired clotting disorders. It’s also sometimes checked in patients with unexplained bleeding or after trauma.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Factor XIII Activity

Frequently asked questions

How often do I need this test?
This test is usually done only when symptoms or medical concerns suggest it’s needed. Follow your doctor’s recommendations for follow-up.
What are the normal reference ranges?
Reference ranges vary by lab, but typically, Factor XIII activity is measured as a percentage (e.g., 50–150%). Your doctor will provide your specific results and compare them to your lab’s standards.
Can lifestyle changes affect Factor XIII levels?
Factor XIII activity is primarily controlled by genetics and clotting factors. Lifestyle factors like diet or exercise don’t typically influence this test directly, but they can impact overall health that may indirectly affect clotting.
  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