The N-Methyl-D-Aspartate (NMDA) receptor is unique to the brain. With brain injury or ischemia, fragments of the NMDA receptor (NR2) break off and appear in the bloodstream. These NR2 fragments generate an antibody response (NR2 ab) from the body. A recently developed blood test (CIS-Biotech, Inc) is able to measure these fragments (NR2) and the antibody (NR2 ab) response. In adult patients who suffer from ischemic stroke, elevated blood levels of NR2 ab correlate with the amount of brain damage on brain magnetic resonance imaging.