Brain’s plumbing may knock out blood test for brain injury

The brain’s got its own set of pipes for flushing waste. The plumbing is delicate, however — a finding that may complicate scientists’ attempts to create a blood test to diagnose traumatic brain injuries.

Bumps to the head can knock proteins out of brain cells. The brain’s plumbing system is supposed to wash these proteins away from the damaged area and eventually into the blood. But new research in mice shows that slight alterations to the brain’s self-cleaning system, even from treating head injuries, can change the levels of proteins flushed into the blood. As a result, the proteins are unreliable markers of injury, researchers report January 14 in the Journal of Neuroscience.