This dissertation traces the historical emergence and transnational uptake of the sexual assault medical forensic exam or SAMFE (commonly known as a "rape kit") as a tool of anti-rape advocacy in emergency medicine since the 1970s and more recent attempts to adapt it for use with refugees and internally displaced persons. Bringing together approaches in medical sociology, socio-legal studies, cultural sociology, and science and technology studies, I analyze the SAMFE as a hybrid medico-legal object that joins law and medicine as a novel form of medical action. I draw on the method of "process tracing" to chart an historical sequence of events to explain a particular outcome: the joining of clinical medicine and criminal law in the SAMFE for the purposes of institutional reform and its effects in domestic and transnational contexts. I first examine reform initiatives led by early forensic nurses in the United States to combine specialized medical care and forensic evidence collection as a new standard of care. Their efforts suggest meso-level processes of legal mobilization in medicine to seek rights to healthcare and rights to justice for patient-victims through new medical routines. I use citation patterns to demonstrate the influence of U.S. forensic nursing models on international guidelines. I then follow these models into a contemporary global initiative to facilitate prosecution of rape as a war crime. After connecting the domestic and humanitarian contexts through the transnational trajectory of the exam, I then, analytically, separate them in order to compare and contrast the impacts and ethical concerns that arise in each context. Combining archival research, fieldwork at international meetings, and over 40 in-depth interviews of healthcare practitioners, activists, lawyers, and other experts, I argue that medical evidence collection techniques help to define what they purport to measure, thereby having profound symbolic and material effects on the credibility of victims' narratives, which crimes are deemed justiciable, and ultimately how events come to be remembered. The case demonstrates how the interweaving of medicine and law gives rise to new forms of institutional hybridity, emergent practices, and methods of knowledge production that fundamentally reshape the patient-provider encounter.