Vitamin C (Ascorbic Acid) Concentration
This test measures the amount of vitamin C, also called ascorbic acid, in your blood. Vitamin C is an essential nutrient that helps protect cells, supports immune function, and aids in wound healing.
["Vitamin C helps your body fight infections and maintain healthy skin, but low levels may indicate deficiencies or health concerns."]
Key facts at a glance
- LOINC
- 61539-3
- Short code
- How much vitamin C PhenX
- Synonyms
- How much vitamin C PhenX
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.4
- Ref high
- 2
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- phenx
- 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 Might You Need This Test?
Your doctor may order this test if you have symptoms of vitamin C deficiency, such as fatigue, frequent infections, or slow wound healing. It may also be used to monitor vitamin C levels in people with certain medical conditions, like malabsorption disorders or chronic illnesses. Additionally, it could be part of a broader nutritional assessment or screening for vitamin-related issues.
What Does the Test Involve?
A blood sample is taken from a vein in your arm. The blood is then sent to a lab where it is analyzed to determine the concentration of vitamin C. The process is quick and typically done in a doctor’s office or clinic.
What to Expect Before or After the Test
There are usually no special preparations needed for this test. You may experience mild discomfort or bruising at the injection site, but this usually goes away quickly. If you are on blood thinners or have a history of bleeding disorders, let your doctor know before the test.
What Are the Possible Results?
The results will show the amount of vitamin C in your blood, measured in milligrams per deciliter (mg/dL). While reference ranges can vary slightly between labs, low levels may suggest a deficiency, while higher levels might be investigated for other reasons like medication use or dietary intake.
Reference range
NCBI: Vitamin C 0.4-2.0 mg/dLN/A
Fasting for 8-12 hours preferred for some tests. Inform about supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low vitamin C levels can lead to scurvy, a condition characterized by fatigue, gum disease, skin hemorrhages, and weakened immunity. Chronic deficiency can also affect healing and increase susceptibility to infections. High levels may indicate over-supplementation, certain medications, or metabolic conditions. Regular monitoring may be needed if you have conditions like celiac disease, Crohn’s disease, or alcoholism, which can interfere with vitamin absorption.
Short name
Vitamin C Level
Frequently asked questions
How often should I get this test?
What can I do to maintain healthy vitamin C levels?
Can vitamin C levels be affected by medications?
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 17, 2026. · Read our editorial policy