What Is Considered a Dangerously High TSH Level?

TSH levels are graded by severity.

TSH Severity Scale

• 4.0–10.0: Mild (subclinical)
• 10.0–20.0: Overt — treatment recommended
• 20.0–50.0: Significant
• Above 50.0: Severe
• Above 100: Critical — myxedema coma emergency

Symptoms of Severe Hypothyroidism

• Severe fatigue
• Hypothermia
• Bradycardia
• Confusion
• Puffy face and hands
• Dry thickened skin
• Hoarse voice

When to Seek Urgent Care

• TSH above 50 with confusion
• TSH above 100 regardless of symptoms
• Hypothermia with slow heart rate