Optimize
Blood test for fatigue

Always tired? Blood test for fatigue: 40+ values in one draw

Waking up tired, low on energy, or fatigue that will not lift: it rarely has a single cause. A comprehensive blood test surfaces the biological factors, from iron deficiency and thyroid function to vitamin D and inflammation, so you know where to start.

01 Scope
40+
biomarkers per test
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 Causes

Which blood values reveal what is behind fatigue?

For persistent fatigue, doctors usually look at the same set of markers: iron status (ferritin first), vitamin B12 and folate, vitamin D, thyroid function (TSH, free T4), blood sugar (HbA1c, glucose) and inflammation (CRP). Each of these can cause fatigue on its own, sometimes it is a combination.

Optimize measures them all at once in the Baseline. Want to dig deeper into iron (serum iron, transferrin, saturation)? That is the Anemia & iron status add-on, in the same draw.

02 Picture

One measurement, broad picture

Instead of chasing tests symptomatically, you get the full picture. The app shows what is optimal per value, which combinations are typical with fatigue and where the most likely starting points are.

Example: low ferritin with normal Hb points to iron deficiency that can play out for years before it leads to anaemia. High TSH with low T4 points to hypothyroidism. Both are classic fatigue causes that can be missed on a narrow test.

03 Next

What do you do with the results?

Per marker, the app gives context: what is normal, what is optimal and where you stand. For mild deviations, lifestyle adjustments can shift the trend.

For significantly off values, especially in combinations that may point to a condition, we recommend talking to your doctor. Optimize does not diagnose or treat.

Understand where your fatigue is coming from. Start with a comprehensive blood test.

Book your blood test

The biomarkers that matter for fatigue

The five areas where the cause of persistent fatigue is most often found, and which we measure in one blood test:

Iron status & anaemia
5 biomarkers
Extended iron status (add-on)
3 biomarkers
Blood sugar
2 biomarkers
Beyond the Baseline?
Add-ons

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

Everything above is in the Baseline, from €225.
Book your blood testBrowse all biomarkers

Clarity on where your energy is leaking

One test covers iron, thyroid, vitamins, blood sugar and inflammation
See where the first wins are, before ordering individual tests
Track whether your values move with your adjustments
FerritinSerum ironTransferrinTransferrin saturationHemoglobinHematocritMCVRDWTSHFree T4Vitamin B12FolateVitamin DMethylmalonic acidGlucoseHemoglobin A1cC-reactive proteinLeukocytesLymphocytesMagnesiumCalciumSodiumPotassiumALTASTCreatinineeGFRFerritinSerum ironTransferrinTransferrin saturationHemoglobinHematocritMCVRDWTSHFree T4Vitamin B12FolateVitamin DMethylmalonic acidGlucoseHemoglobin A1cC-reactive proteinLeukocytesLymphocytesMagnesiumCalciumSodiumPotassiumALTASTCreatinineeGFRFerritinSerum ironTransferrinTransferrin saturationHemoglobinHematocritMCVRDWTSHFree T4Vitamin B12FolateVitamin DMethylmalonic acidGlucoseHemoglobin A1cC-reactive proteinLeukocytesLymphocytesMagnesiumCalciumSodiumPotassiumALTASTCreatinineeGFR
eGFRCreatinineASTALTPotassiumSodiumCalciumMagnesiumLymphocytesLeukocytesC-reactive proteinHemoglobin A1cGlucoseMethylmalonic acidVitamin DFolateVitamin B12Free T4TSHRDWMCVHematocritHemoglobinTransferrin saturationTransferrinSerum ironFerritineGFRCreatinineASTALTPotassiumSodiumCalciumMagnesiumLymphocytesLeukocytesC-reactive proteinHemoglobin A1cGlucoseMethylmalonic acidVitamin DFolateVitamin B12Free T4TSHRDWMCVHematocritHemoglobinTransferrin saturationTransferrinSerum ironFerritineGFRCreatinineASTALTPotassiumSodiumCalciumMagnesiumLymphocytesLeukocytesC-reactive proteinHemoglobin A1cGlucoseMethylmalonic acidVitamin DFolateVitamin B12Free T4TSHRDWMCVHematocritHemoglobinTransferrin saturationTransferrinSerum ironFerritin

How to investigate fatigue via your blood

01 Download
Download the app
Create a free Optimize account.
02 Pick
Pick a broad test
Choose the Baseline or a fatigue-focused test with the markers that matter for energy.
03 Draw
Book a blood draw
Book an appointment at one of the 262+ locations. Fasting is recommended for blood sugar.
04 Understand
See where the cause is
Get clear explanations per area (iron, thyroid, vitamins, blood sugar, inflammation) in the app.
05 Track
Re-test on target
Working on a specific deficiency (e.g. vitamin D, ferritin)? Re-test after 8 to 12 weeks to see the change.
FAQ

Frequently asked questions

The key questions on blood testing for fatigue.

Which blood values matter for fatigue?

Ferritin (your iron store), vitamin B12 and folate, vitamin D, thyroid values (TSH and free T4), blood sugar (HbA1c and glucose) and inflammation marker CRP. All are part of the Baseline blood test by default; the extended iron status (serum iron, transferrin) is an add-on in the same draw.

What is ferritin and why does it matter?
Can vitamin B12 deficiency cause fatigue?
When should I see a doctor?
Do I need a referral for this test?

Take control now.

Where to start

Baseline blood test

€225one-off

Every value that matters for fatigue is in the Baseline. One draw, results usually within 24 hours.

Book your blood test

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