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Tiredness and Fatigue Blood Test

Feb 7, 2026

Tiredness and Fatigue Blood Test

A tiredness and fatigue blood test checks the most common medical causes of exhaustion—including thyroid dysfunction, iron deficiency, vitamin B12 deficiency, vitamin D deficiency, and diabetes—answering the question millions of people ask: "Why am I always tired?" Up to 10% of GP visits are for fatigue, and blood testing identifies treatable causes in the majority of cases.

At Blood Test London, our fatigue profile costs from £245 with results in 2-3 days.

Common Causes of Fatigue (What We Test)

Cause

How Common

Blood Test

Iron deficiency

25% of women

Ferritin, iron studies

Thyroid dysfunction

5% of population

TSH, T4, T3

Vitamin D deficiency

20-40% of UK adults

25-OH vitamin D

Vitamin B12 deficiency

6-20% depending on age

Serum B12

Diabetes/prediabetes

13% have diabetes or prediabetes

HbA1c, glucose

Anaemia

Common

Full blood count

Inflammation

Variable

CRP

Liver dysfunction

Often silent

Liver function tests

Kidney dysfunction

Often silent

Kidney function tests

Find Out Why You're Tired

Our Fatigue Panel Includes

  • Full blood count (anaemia)

  • Iron studies and ferritin

  • Thyroid function (TSH, T4, T3)

  • Vitamin D

  • Vitamin B12 and folate

  • HbA1c (diabetes)

  • Liver function

  • Kidney function

  • CRP (inflammation)

This covers 90%+ of medical causes of fatigue.

When to Test

Get tested if you have:

  • Persistent tiredness despite adequate sleep

  • Fatigue affecting work or daily life

  • Tiredness that's worsened recently

  • Fatigue with other symptoms (hair loss, weight changes, mood changes)

Book Your Fatigue Test

Book via WhatsApp

Price: From £245 | Results: 2-3 days | Doctor review: A doctor always reviews every result

FAQ

Will blood tests definitely find the cause?
In most cases, yes. If tests are normal, lifestyle factors or other conditions may need investigation.

What if everything is normal?
Your doctor will discuss next steps—sleep, stress, and lifestyle factors may be contributing.

Blood Test London by The Wellness. Fatigue testing from £245.