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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, also known as ascorbic acid, in your blood serum. Vitamin C is an essential nutrient that helps support your immune system, skin health, and wound healing.

Quick summary

["Check your vitamin C levels to understand your body’s intake and potential deficiencies."]

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

Key facts at a glance

LOINC
34247-7
Short code
Vit C Ur-sCnc
Synonyms
Vit C Ur-sCnc
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 if you have symptoms of vitamin C deficiency, such as fatigue, frequent infections, or poor wound healing. It may also be used to monitor vitamin C levels in people taking supplements or those with certain medical conditions that affect nutrient absorption.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for a few hours before the test if it’s part of a broader metabolic evaluation, but this isn’t always required. Bring any medications or supplements you’re taking to your appointment.

How the Test Works

A blood sample is taken from a vein in your arm. The blood is then processed to separate the serum, which is analyzed for vitamin C levels using a specialized laboratory method.

What the Results Mean

Results may be compared to general reference ranges to determine if your vitamin C levels are within normal limits, low, or high. Low levels might indicate poor diet, malabsorption issues, or increased metabolic needs.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Vitamin C

Frequently asked questions

What causes vitamin C levels to be low?
Vitamin C deficiency can result from poor diet (lack of fruits/vegetables), certain medications (e.g., some antibiotics or diuretics), smoking, or conditions like celiac disease or Crohn’s disease that affect nutrient absorption.
What if my vitamin C levels are low?
If your levels are low, your doctor may recommend dietary changes (e.g., more citrus fruits, bell peppers) or supplements under medical supervision. They may also investigate underlying causes like malabsorption or chronic illness.
Can vitamin C supplements cause problems if taken in excess?
Yes, very high doses of vitamin C supplements can sometimes cause stomach upset, diarrhea, or kidney issues in sensitive individuals. Always follow your doctor’s guidance on supplement dosages.
  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