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Vitamin C (Ascorbic Acid) Concentration in Serum

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

This test measures the amount of vitamin C, a powerful antioxidant found in your blood serum. Vitamin C helps protect cells from damage and supports immune function.

Quick summary

["Your vitamin C levels may affect your immune health and overall antioxidant protection."]

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

Key facts at a glance

LOINC
60286-2
Short code
Vit C Spec-sCnc
Synonyms
Vit C Spec-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

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of vitamin C deficiency, such as fatigue, frequent infections, or poor wound healing. It could also be used to monitor vitamin C levels in people taking supplements or those with certain medical conditions that affect vitamin absorption or metabolism.

What to Expect Before the Test

No special preparation is needed for this test. You may be asked to fast for a few hours before your blood is drawn, but this depends on your healthcare provider’s instructions. Bring a list of all medications you’re taking, as some may affect vitamin C levels.

What the Test Results Mean

Vitamin C levels can vary based on diet, supplements, and health conditions. Your results will be compared to general reference ranges provided by your lab. Low levels may indicate deficiency, while high levels could be due to supplements or certain medical treatments.

Common Causes of Abnormal Results

Low vitamin C levels may be caused by poor diet, malabsorption issues (like celiac disease or Crohn’s), certain medications, or conditions that affect vitamin metabolism. High levels might result from excessive vitamin C intake from supplements or foods.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Vitamin C

Frequently asked questions

What triggers might affect my vitamin C levels?
Several factors can influence vitamin C levels, including diet (especially if you’re not eating enough fruits and vegetables rich in vitamin C), certain medications (like some antibiotics or diuretics), smoking, alcohol consumption, and underlying health conditions like malabsorption disorders.
Can vitamin C supplements affect my test results?
Yes, vitamin C supplements can raise your blood vitamin C levels. If you’re taking supplements, your healthcare provider may recommend testing at a specific time relative to your last dose to avoid misleading results.
What symptoms might indicate low vitamin C levels?
Symptoms of vitamin C deficiency can include fatigue, frequent infections, gum bleeding, slow wound healing, joint pain, and hair loss. If you experience these symptoms, discuss them with your healthcare provider, who may order this test or other related blood work.
  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