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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 nutrient that helps protect cells from damage and supports healthy skin, immunity, and wound healing.

Quick summary

["Low vitamin C levels may indicate poor absorption, dietary deficiencies, or health conditions affecting nutrient uptake."]

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

Key facts at a glance

LOINC
1903-4
Short code
Vit C SerPl-mCnc
Synonyms
Vit C SerPl-mCnc
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 Is This Test Done?

Your doctor may order this test to check for vitamin C deficiency, assess nutritional status, evaluate gastrointestinal disorders (like malabsorption), or monitor conditions like scurvy or certain medications that deplete vitamin C levels.

What Does the Result Mean?

Results may be compared to general reference ranges for healthy adults, though individual needs vary. Very low levels could signal underlying health concerns requiring further evaluation.

Common Reasons for Testing

Common reasons include diagnosing or monitoring vitamin C deficiency, evaluating symptoms like fatigue, bruising, or slow wound healing, or assessing conditions like Crohn’s disease or celiac disease.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in the arm. The sample is collected in a tube and processed to separate serum or plasma for testing. Avoiding alcohol or certain supplements for a few days before testing may improve accuracy.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin C Level

Frequently asked questions

What are normal vitamin C levels?
Normal vitamin C levels vary by lab and individual factors like age, sex, and health status. Your doctor will interpret results in the context of your overall health and medical history.
Can diet affect vitamin C test results?
Yes, dietary intake of vitamin C can temporarily affect test results. Avoiding high-vitamin C foods or supplements for a few days before testing may help provide a more accurate baseline.
Is this test painful?
The blood draw itself may cause mild discomfort, but most people find it manageable. Your healthcare provider can explain the process and provide tips to minimize any discomfort.
  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