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Vitamin C (Ascorbic Acid) in Serum or Plasma

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

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

Quick summary

["Low vitamin C levels may indicate poor nutrition or health conditions affecting absorption."]

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

Key facts at a glance

LOINC
33979-6
Short code
VGCC-N Bind Ab Ser-sCnc
Synonyms
VGCC-N Bind Ab Ser-sCnc
Category
electrolyte
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 Is This Test Done?

Your healthcare provider may order this test to check for vitamin C deficiency, monitor vitamin C levels after treatment, or evaluate conditions like scurvy, malabsorption syndromes, or chronic illnesses that may deplete vitamin C.

What to Expect Before the Test

No special preparation is usually needed. You may fast for 8–12 hours before the blood draw if instructed, but this is not always required. Bring a list of medications to your appointment.

How the Test Is Performed

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief sting, but the procedure is quick. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to standard reference ranges for healthy adults. Very low levels may signal vitamin C deficiency, while very high levels could indicate recent vitamin C supplementation or certain medical conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin C Level

Frequently asked questions

What causes low vitamin C levels?
Low vitamin C levels can result from poor diet (e.g., limited fruit/vegetable intake), malabsorption disorders (like celiac disease), chronic illnesses (e.g., Crohn’s disease), or excessive alcohol use. Rarely, genetic disorders or certain medications may also contribute.
What symptoms might indicate abnormal results?
Symptoms of vitamin C deficiency include fatigue, gum bleeding, slow wound healing, or frequent infections. High levels may cause nausea, diarrhea, or kidney stones in some cases, but these are less common without intentional supplementation.
How is vitamin C deficiency treated?
Treatment typically involves oral vitamin C supplements or dietary changes to increase intake of vitamin C-rich foods (e.g., citrus fruits, bell peppers). Severe deficiency may require intravenous vitamin C in a hospital setting.
  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