Skip to content
Análisis Médicos

Nutrition blood test

A nutrition blood test assesses certain stores and markers related to nutrition, such as ferritin, vitamin B12, folic acid, vitamin D and some minerals. There is no test that measures every nutrient at once, and no single number that on its own describes nutritional status.

At Análisis Médicos we have designed profiles of different scope and others aimed at specific situations, such as a vegan diet or follow-up after bariatric surgery. The latter are not simply more complete versions: they answer different requirements.

Nutrition blood tests available

If you are not sure which one suits you, there is a guide below the list to help you choose.

How it works

You can order any of our nutrition blood tests without your doctor having to request it:

Price
From €129.00
Prescription
Not needed
Appointment
Not needed
Results
1 to 7 working days
  • Your test request, in minutes. Order the profile you want and it arrives in your inbox straight away, with the preparation instructions.
  • Wherever suits you, with no appointment. You can have your test at any of the 45 partner centres, and the laboratory emails you the results within a few days.
  • With an invoice. When you order, you receive an invoice you can submit if you have reimbursement health insurance. How it works, step by step.

How to choose your nutrition blood test

This is not medical advice and does not replace a consultation: it is the reasoning I would use to choose, in case it helps you decide which one to order.

For a first review, the basic nutrition blood test brings together the most common markers of iron, vitamins and thyroid function.

To extend the assessment, the full nutrition blood test adds iron studies, trace minerals and urine. The advanced nutrition blood test includes less common tests, such as vitamins A and E, copper or ionised calcium. It is marked as secondary because that breadth does not add the same for everyone.

If you follow a vegan diet, the vegan diet nutrition check focuses on the deficiencies worth watching in that context, with particular attention to vitamin B12.

After bariatric surgery, the post-bariatric check includes micronutrients and markers specific to that follow-up. It does not replace the reviews scheduled by the team that performed or monitors the operation.

Dr. Antonio Mas

Iron, vitamins and minerals tell different parts of the story

Ferritin is used to estimate iron stores, but it can also rise with inflammation. That is why it is best understood together with the full blood count and, where appropriate, with other iron parameters.

Vitamin B12 is usually the first marker in the assessment. Methylmalonic acid or homocysteine can add information in specific situations, but they are not equivalent to each other and they do not turn an isolated number into an automatic diagnosis. Homocysteine is also affected by folate and other factors.

Vitamin D, folic acid and minerals such as zinc, selenium or copper answer different questions. Having them together in one profile makes the sample easier, but it does not mean they should always be requested together.

What you eat and what is measured are not the same

Diet influences these markers, but so do intestinal absorption, blood loss, inflammation, medication and supplements. A varied diet does not on its own guarantee that all stores are adequate, and an abnormal value does not automatically identify its cause.

When a broader profile makes sense

Breadth is best justified when there is a situation that changes the risk of deficiency, such as bariatric surgery, a diet with significant exclusions or specific clinical follow-up. Outside those contexts, more tests can produce findings that are hard to interpret without improving the decision.

Before your blood test

The nutrition profiles in this category require 8 to 12 hours of fasting, depending on the profile page. You can drink water during that time.

Mention the supplements you take and the time of the last dose. Do not stop a prescribed supplement or treatment on your own. The instruction can vary with the aim of the profile: some checks are designed precisely to assess the status reached with your usual supplements.

If the profile includes urine, also follow the collection instructions on its page.

Frequently asked questions

Are ferritin and iron the same?
No. Blood iron can vary throughout the day. Ferritin helps estimate stores, although it can also rise when there is inflammation.
Does a nutrition blood test measure every nutrient?
No. Each profile brings together a specific selection of vitamins, minerals and other markers. The profile page shows exactly what it includes.
Do I have to stop supplements before the blood test?
There is no single rule. It depends on the supplement and the aim of the check. Look at the preparation on the profile page and do not stop anything prescribed on your own.
Is there a specific profile if I follow a vegan diet?
Yes. The vegan diet nutrition check is aimed at the markers that deserve particular attention on that type of diet, including vitamin B12.
Is the post-bariatric check suitable for any nutrition review?
No. It is designed for follow-up after bariatric surgery and includes tests specific to that situation.

If you already have your results

A figure only makes sense in its context. Medical history, symptoms, medication and the conditions of the sample can change what it means. Results are assessed in a consultation; this page is for comparing and ordering profiles.

The laboratory sends you the results directly. You can then review them with the professional of your choice.

See nutrition blood tests

Guide reviewed by Dr. Antonio Mas, specialist in Endocrinology and Nutrition, Spanish medical licence no. 080846289, in September 2026.

And if you were looking for something else, here are all the blood tests in the catalogue, grouped by topic.