Vitamins, minerals and amino acids
Vitamine C
The amount of vitamin C in the blood; a severe deficiency is rare, a mild deficiency occurs with a one-sided diet.
Everything about this testWhat it measures
Vitamin C (ascorbic acid) is needed to form connective tissue, bones, teeth and blood vessels, for the immune system and for the absorption of iron, and it acts as an antioxidant. The body cannot make it itself and gets it from fresh fruit, vegetables and potatoes. The value in the blood mainly follows recent intake. Vitamin C breaks down quickly, including in a blood sample after the blood draw.
- Vitamin C deficiency with a very one-sided diet low in fruit and vegetables, for example in older people living alone or with excessive alcohol use
- Rarely: scurvy, the result of a long-term severe deficiency
High
A high value comes from eating a lot of fruit and vegetables or from supplements and is usually harmless; any excess is passed in the urine. According to the Netherlands Nutrition Centre (Voedingscentrum), an intake of more than 2 grams per day can cause bowel symptoms or diarrhea. Otherwise, a high value causes no symptoms on its own and needs no follow-up.
Low
A low vitamin C fits a low intake; according to the Dutch Society for Clinical Chemistry (NVKC), a clearly low value points to a deficiency. A deficiency develops mainly when eating little fresh fruit and vegetables, for example in older people living alone with poor eating habits, with excessive alcohol use or with an eating disorder. Symptoms of a deficiency are tiredness, weight loss, reduced resistance to infection, joint symptoms, bruises and poor wound healing; a long-term severe deficiency can lead to scurvy, with bleeding gums and bleeding under the skin. A slightly low value without symptoms can also be caused by the sample being in transit for too long.
If your result is abnormal
With a clearly low value and matching symptoms, the GP looks at diet and alcohol use and usually advises more fruit and vegetables or a supplement. With a slightly low value without symptoms, the test is sometimes repeated, because the value can come out too low due to the transport of the sample.
Reliability
A clearly low value fits a low intake, but vitamin C is unstable in a blood sample: if transport takes too long or is too warm, or with exposure to light, the value drops, which can suggest a deficiency that is not there. The test is mainly used when a deficiency is suspected or to monitor treatment.
Limitations
- Vitamin C breaks down quickly in the sample; laboratories ask for the blood to be put on ice immediately after the blood draw and processed chilled.
- Fruit, juice or a supplement shortly before the blood draw temporarily raises the value.
- With a serious accident, burns or a serious illness, the body uses more and the value can drop.
- Reference values differ per laboratory.
How common is this
According to the Dutch Society for Clinical Chemistry (NVKC), scurvy, the result of a severe vitamin C deficiency, is a thing of the past in countries such as the Netherlands. Milder deficiencies still occur, especially in older people with poor eating habits and with excessive alcohol use. How often a mild deficiency occurs in the Netherlands is not well known.
Who is this useful for
Useful when a deficiency is suspected with a very one-sided diet low in fruit and vegetables, such as in older people living alone, with excessive alcohol use or an eating disorder, together with symptoms such as bleeding gums, bruises or poor wound healing. In healthy people without symptoms the result says little; with a varied diet a deficiency is rare.
Downsides and risks
- Breakdown of vitamin C in the sample can cause a falsely low result, leading to unnecessary worry or unnecessary supplements.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results