Vitamin C (Ascorbic Acid) in Serum or Plasma
This test measures the amount of vitamin C (ascorbic acid) in your blood, which helps support your immune system, skin health, and iron absorption.
["Vitamin C levels can indicate nutritional status and potential deficiencies."]
Key facts at a glance
- LOINC
- 9631-3
- Short code
- Visc Smn
- Synonyms
- Visc Smn
- 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 healthcare provider may order this test if you have symptoms of vitamin C deficiency (like fatigue, bruising easily, or slow wound healing), suspected scurvy, or if you have conditions that affect vitamin absorption (e.g., gastrointestinal disorders). It may also be checked during pregnancy, in certain chronic illnesses, or as part of routine screening for nutritional deficiencies.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if serum/plasma is collected, but this depends on your lab’s instructions. Bring any medications or supplements you’re taking, as they could affect results.
How the Test Is Performed
A blood sample is drawn from a vein in your arm by a healthcare professional. The blood is then processed to separate serum or plasma for testing. Results are typically available within 1–3 business days.
What the Results Mean
Results are compared to reference ranges for your age, sex, and health status. Low levels may suggest vitamin C deficiency, while high levels could indicate recent vitamin intake, certain medications, or metabolic conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Vitamin C Level
Frequently asked questions
Low vitamin C levels can weaken immunity, cause skin problems, or contribute to chronic diseases like heart disease or certain cancers. High levels may not always indicate a problem but could signal overconsumption or underlying metabolic issues.
How can I naturally increase my vitamin C levels? Eat fruits like oranges, kiwi, and berries, or vegetables such as bell peppers and broccoli. Ask your provider about supplements if needed.
How often should I get this test? Your provider will determine frequency based on your health status, symptoms, or risk factors—typically every few months for high-risk individuals.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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