As is the case with neuroimaging, there are no currently available lab tests that can diagnose migraine headaches. There are, however, a number of tests that may be ordered by your doctor in order to exclude other causes of headache.

Blood and Urine Tests

Blood and urine tests can rule out infection and certain disease-based causes of chronic headache such as temporal arteritis, thyroid disease, kidney failure, and anemia. Blood tests may include a complete blood count (CBC), a comprehensive metabolic panel (CMP), and other blood chemistry panels.

A high white blood cell count indicates infection, while a low red cell count points to anemia, both potential causes of secondary headache. An elevated erythrocyte sedimentation rate (sometimes called a sed rate) may mean that the head pain is caused by temporal arteritis.

Other Lab Tests

Infections such as meningitis and conditions causing bleeding on the brain can cause severe headache. A lumbar puncture, also known as a spinal tap, is a procedure that involves removing cerebro-spinal fluid (or CSF) from the base of the spine in order to examine the fluid for infection or blood. It is not useful in migraine diagnosis, but lumbar puncture may be used to rule out a subarachnoid hemorrhage if neuroimaging is normal but other factors point to potential bleeding. The procedure is also used to assess CSF pressure when increased intracranial pressure (or swelling of the brain) is suspected.