Vitamins, minerals and amino acids
Vitamine B2
The amount of riboflavin in the blood; a deficiency is rare in the Netherlands and a result without symptoms says little.
Everything about this testWhat it measures
Vitamin B2 (riboflavin) is needed for the energy supply of cells. The body converts it into the active forms FMN and FAD, which act as helper substances in many metabolic processes. Riboflavin is found mainly in milk and dairy products, and also in meat, vegetables, fruit, bread and grain products. The test measures riboflavin or the active form FAD in blood; which form differs per laboratory.
- Vitamin B2 deficiency with a very one-sided diet
- Deficiency with malnutrition, excessive alcohol use or poor absorption in the gut
High
A raised vitamin B2 is almost always caused by supplements or a multivitamin. The gut absorbs only a small part of a large amount, and any excess is passed in the urine. No harmful effects of too much riboflavin are known and no tolerable upper limit has been set. A high value needs no follow-up.
Low
A low vitamin B2 may fit a deficiency, but that is rare in the Netherlands because a normal diet usually provides enough riboflavin. A deficiency occurs mainly with a very one-sided diet, malnutrition, excessive alcohol use or a bowel disease, often together with deficiencies of other B vitamins. Symptoms of a deficiency are skin changes around the mouth and tongue, such as cracks in the corners of the mouth, and inflammation around the nose. A slightly low value without these symptoms says little.
If your result is abnormal
With a low value and matching symptoms, the GP looks at diet, alcohol use and possible bowel diseases and often checks other vitamins as well. A deficiency is usually corrected with diet or a supplement. With a slightly low value without symptoms, follow-up is usually not needed.
Reliability
The test is mainly used when there is a specific suspicion of malnutrition or an absorption disorder. Measurement methods and reference values differ between laboratories. A single value says little without matching symptoms and risk factors.
Limitations
- Riboflavin breaks down under the influence of light; the sample must be packed away from light immediately after the blood draw, otherwise the value may come out too low.
- Supplements and multivitamins raise the value.
- Laboratories measure different forms (riboflavin or FAD) with their own reference values; results cannot simply be compared.
How common is this
A vitamin B2 deficiency is rare in the Netherlands in healthy people with a varied diet; according to the Netherlands Nutrition Centre (Voedingscentrum), you usually get enough riboflavin from your diet. There are no reliable Dutch figures on how often a deficiency occurs.
Who is this useful for
Only useful when a deficiency is suspected, for example with malnutrition, an eating disorder, excessive alcohol use or a bowel disease with poor absorption, together with symptoms of the mouth, tongue or skin. In healthy people without symptoms, including those with a vegetarian or vegan diet, a single result says little. The same applies to tiredness without other symptoms.
Downsides and risks
- A slightly abnormal value, for example due to a sample that was exposed to light, can lead to unnecessary worry or unnecessary further testing.
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