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Vitamin C (Ascorbic Acid) in Serum

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

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

Quick summary

["Check your vitamin C levels to ensure proper immune support and antioxidant protection."]

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

Key facts at a glance

LOINC
1904-2
Short code
Vit C Ur Ql
Synonyms
Vit C Ur Ql
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to evaluate vitamin C levels, especially if you have symptoms like fatigue, frequent infections, or signs of scurvy (a rare vitamin C deficiency). It can also help monitor vitamin C intake from supplements or diet.

What Does the Result Mean?

Low levels might indicate poor absorption, dietary deficiencies, or certain medical conditions. High levels could suggest over-supplementation or specific metabolic processes. Results are interpreted by your healthcare provider based on your overall health.

Common Reasons for Testing

Tests for vitamin C are often done to diagnose or monitor conditions like scurvy, vitamin C deficiency, or to assess how well supplements are working. It may also be part of a broader nutritional evaluation.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw. Avoid taking vitamin C supplements 24 hours before the test if possible, as this could affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Vitamin C’s Role in Health

Short name

Serum Vitamin C

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the findings with you during your follow-up visit.
Can I take vitamin C supplements before the test?
It’s best to avoid vitamin C supplements 24 hours before testing to get an accurate reading. If you have a medical reason to take them, discuss this with your provider first.
What if my vitamin C level is low?
If your levels are low, your provider may recommend dietary changes, increased vitamin C intake, or further testing to identify the cause. They may also suggest supplements under medical supervision.
  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