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Heparinized Plasma Factor II Activity (Prothrombin Activity)

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

This test measures how well your blood’s clotting factor II (prothrombin) functions in plasma collected with heparin, a blood thinner. It helps assess your blood’s ability to clot under controlled lab conditions.

Quick summary

["This test helps check for bleeding disorders or how well your blood clots normally."]

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

Key facts at a glance

LOINC
3268-0
Short code
Heparin CF II Ag PPP IA-mCnc
Synonyms
Heparin CF II Ag PPP IA-mCnc
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
ia
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

What This Test Measures

Factor II (prothrombin) is a protein in your blood that plays a key role in the clotting process. This test evaluates its activity level in plasma, which can be affected by conditions like liver disease, vitamin K deficiency, or certain medications.

Why It’s Done

Doctors may order this test to diagnose or monitor bleeding disorders, evaluate liver function, or check for issues with blood clotting before surgery or other procedures.

How the Test Works

A small blood sample is taken and mixed with heparin to prevent clotting. The lab then measures how long it takes for the sample to clot under controlled conditions, reflecting Factor II’s activity.

What to Expect Before the Test

No special preparation is needed, but inform your healthcare provider about any medications (like blood thinners) or recent illnesses that might affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Factor II Activity (Prothrombin Activity)

Frequently asked questions

What might cause abnormal results?
Low Factor II activity can indicate liver disease, vitamin K deficiency, or certain medications that interfere with clotting. High levels may rarely suggest inherited clotting disorders.
How does this test differ from other clotting tests?
Unlike other tests (e.g., PT/INR), this measures Factor II activity directly in heparinized plasma, giving a focused view of its function without relying on other clotting factors.
Can I get this test at home?
No, this test requires a blood draw in a clinical setting, as it needs precise lab conditions to measure clotting activity accurately.
  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