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Serum Vitamin C (Ascorbic Acid) Concentration

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

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

Quick summary

["Your vitamin C levels help assess immune health and antioxidant status."]

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

Key facts at a glance

LOINC
47135-9
Short code
Vit C p dose SerPl-sCnc
Synonyms
Vit C p dose SerPl-sCnc
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 to check for vitamin C deficiency, monitor vitamin C levels in certain conditions (like chronic illnesses), or evaluate how your body absorbs and uses vitamin C. It can also help diagnose or manage scurvy or other vitamin-related disorders.

What Does a Low or High Level Mean?

Low levels may indicate vitamin C deficiency, which can weaken immunity, cause fatigue, or lead to bleeding gums. High levels might suggest overconsumption, kidney issues, or certain medications affecting vitamin C metabolism.

How Is This Test Performed?

A blood sample is drawn from a vein, usually in your arm. The serum is separated and analyzed using a sensitive immunoassay method to measure vitamin C concentration.

What Should You Do Before the Test?

Avoid taking large doses of vitamin C supplements 24 hours before the test, as this could affect results. Eat normally, but avoid heavy exercise or stress that day.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Vitamin C Level

Frequently asked questions

How long does it take to get results from this test?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the results with you during your follow-up visit.
Can vitamin C levels be affected by diet?
Yes, diet plays a key role. Fresh fruits and vegetables (especially citrus, bell peppers, and strawberries) are excellent sources of vitamin C. However, certain foods or medications (like some antibiotics or diuretics) may temporarily alter levels, so it’s best to discuss your diet and medications with your provider before testing.
Is this test painful?
The blood draw itself is usually mild discomfort, like a pinch, but most people tolerate it well. The site may feel sore for a few hours afterward. If you’re anxious, let your healthcare provider know they can use a smaller needle or take extra precautions.
  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