Your doctor will diagnose a migraine by asking you questions about your health and lifestyle and by examining you. There are no lab tests that can confirm a diagnosis. Migraines can be difficult to diagnose because symptoms resemble those of other headache conditions. For example, many people have been diagnosed with sinus headaches when they actually have migraines. As a result, migraines are underdiagnosed and undertreated.

Your doctor may use the International Headache Society's criteria to diagnose migraines. You may be diagnosed if you experience 5 or more headache attacks without an aura (or 2 attacks with an aura) that last from 4 to 72 hours without treatment and are accompanied by symptoms of nausea, vomiting, or sensitivity to light or noise.

Your doctor will check your symptoms and decide whether you need to have tests to rule out other conditions that might be causing your headaches. Tests may include:

• MRI or CT scan, which may be used to rule out tumors or bleeding in the brain.
• Lumbar puncture (also called a spinal tap), which may be done if your doctor thinks that you might have another condition such as meningitis or bleeding in the brain.
• Sedimentation rate (a blood test), which may help determine whether another condition is causing inflammation related to your headaches.