What Blood Tests Should I Get for Brain Fog?

The top blood tests for brain fog are TSH, vitamin B12, ferritin, fasting glucose, and a comprehensive metabolic panel. Thyroid dysfunction is a leading cause of mental cloudiness. These tests also identify B12 deficiency, iron deficiency, and blood sugar issues that impair cognition.

Possible Causes

HypothyroidismHashimoto's ThyroiditisVitamin D DeficiencyAnemiaInsulin Resistance

Recommended Tests

TSH

$8

Measures thyroid-stimulating hormone to evaluate thyroid function. TSH is the most sensitive marker for detecting thyroi...

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Free T4

$8

Measures the unbound, active form of the thyroid hormone T4. Helps assess thyroid function and diagnose thyroid conditio...

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B12

$8

Measures B12 levels essential for nerve function, DNA synthesis, and red blood cell formation.

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Ferritin

$9

Measures iron storage protein. Best indicator of total body iron stores.

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Fasting Glucose

$6

Measures blood sugar levels after fasting. Used to screen for diabetes and monitor blood sugar control.

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CMP

$10

Measures 14 substances including glucose, electrolytes, kidney and liver function markers.

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Vitamin D

$22

Measures vitamin D status. Deficiency is common and linked to bone health, immune function, and mood.

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When to See a Doctor

If your brain fog is severe, rapidly worsening, or accompanied by alarming symptoms (chest pain, shortness of breath, high fever), seek immediate medical attention. Blood tests are a valuable first step, but they don't replace evaluation by a healthcare professional.

Frequently Asked Questions

Related Symptoms

FatiguePoor ConcentrationDepressionInsomnia

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Content reviewed for accuracy by the JustLabs editorial team.