Tyler's Law directs the Department of Health and Human Services to study and issue guidance on whether hospitals should routinely test for fentanyl when patients arrive at emergency departments with overdoses. The Secretary must complete the study within one year of the law's enactment, examining how often hospitals currently test for fentanyl, the costs involved, potential benefits and risks to patients, and how testing might affect patient privacy and the doctor-patient relationship. Within six months after finishing the study, the Secretary must issue guidance addressing whether fentanyl testing should become standard practice, how to ensure clinicians know which substances their routine drug tests screen for, and how fentanyl testing might affect future overdose risk and overall health outcomes. This legislation affects hospital emergency departments across the country and impacts patients experiencing overdoses. The bill establishes clear timelines with the study due within one year and guidance to follow within eighteen months total.