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Oxidative stress marker (total antioxidant capacity) in serum/plasma

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

This test measures your blood’s ability to neutralize harmful free radicals, which can cause cell damage. It helps assess your body’s natural antioxidant defenses.

Quick summary

["Your blood’s antioxidant protection may be low if you’re at higher risk for chronic inflammation or oxidative stress."]

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

Key facts at a glance

LOINC
10243-4
Short code
O2 Ct IVC-sCnc
Synonyms
O2 Ct IVC-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
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

What Does This Test Measure?

This test evaluates the combined activity of various antioxidants in your blood, including vitamins (like vitamin C and E), enzymes, and other molecules that protect cells from oxidative damage. Free radicals are unstable molecules that can damage cells if left unchecked, potentially contributing to long-term health issues.

Why Might You Need This Test?

Doctors may order this test if you have symptoms of oxidative stress, such as chronic fatigue, frequent infections, or signs of inflammation. It’s also sometimes used in research or monitoring conditions like heart disease, diabetes, or certain cancers where oxidative stress plays a role.

What to Expect Before the Test

No special preparation is needed, but you may fast for 8–12 hours before the draw if your lab requires it. Bring your lab results and any medications you’re currently taking to your appointment.

What Happens During the Test?

A healthcare provider will draw blood from a vein in your arm. The blood sample will be sent to a lab where it is analyzed for total antioxidant capacity using a specialized method, such as an enzymatic assay.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Antioxidant Status (TAS)

Frequently asked questions

What Does a Low or High Result Mean?
A lower-than-expected result may indicate insufficient antioxidant defenses, which could be linked to chronic inflammation, poor diet, or certain medical conditions. A higher-than-expected result might suggest unusually strong antioxidant activity, possibly due to high vitamin intake or specific health interventions.
How Does This Test Compare to Other Tests?
This test is distinct from individual antioxidant vitamin levels (like vitamin C or E) and doesn’t replace other blood tests, such as those for inflammation markers (e.g., CRP) or glucose. It provides a broader picture of your body’s antioxidant capacity.
Can Lifestyle Changes Affect This Test?
Yes! Eating antioxidant-rich foods (like fruits, vegetables, and nuts), staying hydrated, and avoiding smoking or excessive alcohol can influence your results. Regular exercise and managing stress may also support your body’s natural antioxidant response.
  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