Vitamin test: your vitamins and minerals in one blood draw

A vitamin test can show whether your blood holds enough of what your body needs. Your body does not make most vitamins itself. You get them from food and, for vitamin D, from sunlight.

A deficiency often builds up slowly. Symptoms such as tiredness are then vague and fit many causes. A blood value gives you a measurement instead of a guess.

The vitamin test may be useful for people who more often lack vitamins or iron:

• you eat a vegetarian or vegan diet, since vitamin B12 is found mainly in animal products
• you spend little time outdoors or have darker skin, which can lower your vitamin D
• you have taken stomach acid inhibitors or metformin for a long time, which can reduce B12 absorption
• you have heavy periods or give blood regularly
• you take supplements and want to know what they do

The vitamin test measures 11 values, in five groups:

• Vitamin D (25-OH): the form in which your body stores vitamin D.
• Vitamin B12 and folate: two B vitamins for making red blood cells and for your nervous system.
• Magnesium and zinc: two minerals involved in many processes in your body.
• Iron, ferritin, transferrin and transferrin saturation: together, your iron status. Ferritin shows your iron stores, the other three the iron your blood carries now.
• Haemoglobin and MCV: whether anaemia is present. MCV also shows whether your red blood cells are smaller or larger than average.

Your vitamin test results show, value by value, whether each sits below, within or above the reference range. That can bring a vitamin D deficiency or low iron stores into view.

Haemoglobin and MCV can help explain a deficiency. A low MCV fits iron deficiency more often, a high MCV more often too little B12 or folate.

The test does not make a diagnosis. It gives you measurements to discuss with a doctor.

For the vitamin test, blood is drawn from a vein in your arm. That happens at a collection point near you and takes a few minutes.

After you order, Mijnbloedtest arranges your referral through ZorgDomein. Allow one working day. Order in the evening or at the weekend, and that working day starts on the next working day.

The ZorgDomein email contains a barcode, which you show at the collection point. Your order confirmation is not a referral. The collection points are run by independent, certified laboratories.

A vitamin test is most useful when you have a specific question your blood can answer, for example:

• you have been tired for weeks and wonder whether iron, B12 or vitamin D play a part
• you recently started eating less meat or none at all
• you take supplements and want to see whether your values have changed
• you want a baseline to compare against later

Without a question or a reason, testing often adds little. A value outside the range then usually means nothing.

Each value in your vitamin results comes with the reference range of the lab that measured your blood. Reference ranges differ between laboratories, so always read a number next to its range.

A value just outside the range does not always mean a deficiency. With vitamin D the season matters. Your value is often lower in winter than in summer.

Discuss values outside the range with your GP.

For the vitamin test you do not need to fast. Fasting and a draw before 10:00 do give a slightly cleaner iron value. Drinking water is always fine.

Have you had a fever, an infection or a vaccination in the past two weeks? Then wait before giving blood. Ferritin and iron react to inflammation and would otherwise give a distorted picture.

Do you take supplements with vitamin D, B12, folate or iron? Then they show up in your values. Keep that in mind when you read your results.

Your vitamin results appear value by value in your Mijnbloedtest account, with the reference range alongside. Every result comes with a professional assessment from a BIG-registered doctor.

Want treatment based on a result? Discuss your results with your GP first.