What Is the Vitamin C Test?
Vitamin C (ascorbic acid) is an essential water-soluble vitamin that the body cannot produce itself. It supports immune function, collagen synthesis, wound healing and iron absorption. Blood levels are measured when deficiency is suspected.
Normal Vitamin C Range
| Level | Range (mg/dL) | Interpretation |
|---|---|---|
| Normal | 0.4–2.0 | Adequate vitamin C status |
| Low | 0.2–0.4 | Suboptimal — at risk of deficiency |
| Deficient | Below 0.2 | Deficiency — supplementation needed |
| Scurvy | Below 0.1 | Clinical scurvy — urgent treatment required |
Symptoms of Vitamin C Deficiency
- Fatigue and irritability
- Swollen, bleeding or inflamed gums
- Slow wound healing
- Easy bruising
- Dry, rough skin and corkscrew hairs
- Joint pain
- Scurvy (severe deficiency): haemorrhage, tooth loss, anaemia
Who Is at Risk of Deficiency?
- Smokers (need 35 mg more/day than non-smokers)
- People with very limited fruit and vegetable intake
- Alcohol dependence
- Malabsorption conditions (IBD, bariatric surgery)
- Patients on dialysis
Good Food Sources of Vitamin CCitrus fruits, red peppers (highest source), kiwi, broccoli, strawberries and blackcurrants. Cooking destroys vitamin C — raw fruits and veg preserve it best.
FAQs
Can you have too much vitamin C?
High doses (above 2,000 mg/day) can cause kidney stones, diarrhoea and nausea. Blood levels rarely become toxic from food alone.
Does vitamin C help with colds?
It may slightly reduce duration of colds but does not prevent them in most people. It is most beneficial in those who are deficient.
Is fasting required?
No — fasting is not required for this test.
Medical Disclaimer: Vitamin C deficiency is easily treatable. If scurvy is suspected, treatment should begin immediately without waiting for test results.