Ask the Experts

Can A Blood Test Diagnose ADHD?

“I’ve read that ADHD is caused by a deficiency of norepinephrine. Can a blood test show such a deficiency and diagnose ADHD?”

Researchers discovered that ADHD is caused by a deficiency of norepinephrine (or one of its building blocks, dopa or dopamine) through extensive analysis of spinal fluid, blood, and urine. Newer studies have used brain-imaging to clarify this connection.

Because the studies are time-consuming and expensive, they aren’t used outside of the research laboratory. To date, we do not have a biological test to diagnose ADHD. Instead, the diagnosis is based on clinical history and observations.