What Is a TSH Blood Test For?

A TSH test screens for thyroid dysfunction by measuring Thyroid-Stimulating Hormone.

Why It's the Best Screening Test

• Most sensitive — detects dysfunction before T4 changes
• Simple blood draw, no fasting needed

What Results Mean

• High TSH = hypothyroidism (underactive)
• Low TSH = hyperthyroidism (overactive)
• Normal = thyroid function is normal

When to Get Tested

• Symptoms: fatigue, weight changes, cold/heat intolerance
• Family history of thyroid disease
• Pregnancy planning
• Routine: every 5 years from age 35