Optimize
Vitamin deficiencies

Vitamin deficiency test: D, B12, iron and folate in one draw

Tired, low in winter, tingling, or just curious? Deficiency symptoms overlap heavily, so guessing from complaints does not work. One blood test measures your vitamin D, vitamin B12, folate and iron status together, so you know what to supplement and what not to.

01 Coverage
4
deficiencies in one draw: D, B12, folate and iron
02 Reach
262+
draw locations in the Netherlands
See all locations
03 Access
No
referral needed

From €225, no referral needed, does not count towards your deductible.

01 Measure

Which deficiencies does a blood test cover?

The four deficiencies that are most common and cause the most complaints: vitamin D (bones, muscles, immune system), vitamin B12 (red blood cells and the nervous system), folate (cell division and blood production) and iron, strictly a mineral, measured through ferritin (your iron stores).

All four are part of the Baseline blood test by default. No need to pick which deficiency to test: you measure them together, alongside 40+ other blood values.

02 Why

Why symptoms mislead

A vitamin D deficiency, a B12 deficiency and an iron deficiency produce largely the same complaints: fatigue, low energy, poor concentration. Without measuring there is no telling which deficiency is at play, or whether there is no deficiency at all and the cause lies elsewhere.

Supplementing blindly does not solve that. Supplement the wrong thing and the complaints stay; and for some nutrients, like iron, too much is actively harmful. Measure first, then supplement with purpose.

03 Next

From result to plan

For every value the app shows what is normal, what is optimal and where you stand. With a confirmed deficiency you supplement through food or a targeted supplement, and when your B12 status is unclear, the Vitamin B12 status add-on (with MMA) settles whether a low B12 is a true functional deficiency.

Re-test after 8 to 12 weeks to see the deficiency recover. For strongly abnormal values we advise contacting your doctor; the result shares easily as an attachment.

Want to know which deficiency is real? Measure vitamin D, B12, folate and your iron status in one blood test.

Test your vitamins

The biomarkers behind each deficiency

For each deficiency we measure more than one value, so you also see whether a shortage already shows in your blood picture:

Vitamins
3 biomarkers
Iron status
2 biomarkers
Extended iron status (add-on)
3 biomarkers
Functional B12 status (add-on)
1 biomarkers
Beyond the Baseline?
Add-ons

Beyond the Baseline, targeted add-ons let you go deeper into a specific marker or system.

See all biomarkers

How to test for a vitamin deficiency

01 Download
Download the app
Create a free account in the Optimize app.
02 Pick
Pick the Baseline
Vitamin D, B12, folate and ferritin are included by default. Unsure about your B12? Add the Vitamin B12 status add-on (with MMA).
03 Draw
Book a blood draw
Choose one of the 262+ draw locations and a time that suits you.
04 Understand
See which deficiency is at play
For every value the app shows where you stand, explained in plain language.
05 Track
Supplement with purpose and re-test
Working a deficiency away? Re-test after 8 to 12 weeks to see the recovery.

Our duty of care

We only reach out if something needs your attention.

Every blood result is screened by an automated triage system and reviewed by our physician when something stands out. No needless alarm — but a clear signal the moment there's genuinely something to act on.

Read about our approach →
FAQ

Frequently asked questions

The key questions about testing for vitamin deficiencies.

How can I test for a vitamin deficiency?

Through a blood test. With Optimize you order it yourself, no doctor's referral needed. Vitamin D, vitamin B12, folate and your iron status (ferritin) are part of the Baseline blood test by default.

What does a vitamin deficiency test cost?
Which symptoms fit a vitamin D deficiency?
How do I know whether I have a vitamin B12 deficiency?
Is an iron deficiency a vitamin deficiency?
Do I need to fast for this test?
What if the test shows a deficiency?

Take control now.

Where to start

Baseline blood test

€225one-off

One comprehensive draw at a location near you; you can always extend with add-ons.

Book your blood draw

No referral needed · Results within 24 hours

  • 40+ biomarkers in one blood draw
  • Results within 24 hours
  • Explained in plain language, not a lab sheet
  • No referral, no waiting list
  • 262 draw locations in the Netherlands
  • Your own dashboard, with trends on every retest

Prefer to read on first? Blood test