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Serum/Plasma Vitamin G (Vitamin K) Activity (Anticoagulant Effect)

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

This test measures how well your blood can clot, which depends on vitamin K. Low levels may affect blood clotting and increase bleeding risk.

Quick summary

["Vitamin K helps your blood clot properly; low levels can raise your risk of excessive bleeding."]

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

Key facts at a glance

LOINC
110739-0
Short code
RV IgG Msmt Ser
Synonyms
RV IgG Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 Is Done

Your doctor may order this test if you have bleeding problems, trouble clotting, or conditions like liver disease, malnutrition, or long-term antibiotic use that can affect vitamin K levels. It may also be checked before surgery or if you’re taking certain medications that influence blood clotting.

What to Expect Before the Test

No special preparation is needed, but inform your doctor about any medications (including blood thinners) or supplements you’re taking, as they can impact results. Avoid eating or drinking for 12 hours before testing if instructed.

How the Test Is Performed

A blood sample is drawn from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort. The sample is sent to a lab for testing.

What the Results Mean

Results are compared to a standard range to determine if your vitamin K levels are within normal limits. Low levels may indicate vitamin K deficiency or conditions affecting absorption, while high levels could suggest overconsumption or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin K Activity

Frequently asked questions

What does a low vitamin K level mean?
A low vitamin K level may mean your body isn’t absorbing enough vitamin K or you have conditions like liver disease, celiac disease, or long-term antibiotic use that disrupt its production. It can increase your risk of bleeding, especially if you’re taking blood thinners like warfarin.
What does a high vitamin K level mean?
High vitamin K levels are less common but may occur if you’ve taken too much vitamin K from supplements or certain medications. It can sometimes interfere with blood thinners, so your doctor will monitor you closely if you have this result.
How often should I get this test?
Your doctor will decide how often you need this test based on your health, medications, and symptoms. If you have a condition like liver disease or take blood thinners, you may need it more frequently.
  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