The observation that Black patients received tPA with a lower frequency than White patients may indicate that Black individuals arrive in the ED with a last known well that places them outside of the time window for thrombolytic treatment (at most 4.5 hours) with a greater frequency than White patients, or that Black individuals are presenting with more hemorrhagic strokes which are not amenable to tPA treatment, as opposed to ischemic strokes which are. This evidence concerns the gene PLAT and hemorrhagic stroke.