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An international team of researchers from George Mason University, Harvard University, and the University of Tokyo have used artificial intelligence to map the global underground market for illegal kidney transplants, finding that the United States consistently ranks among the world’s largest illicit importers.
The study, led by Naoru Koizumi, a professor at the Schar School of Policy and Government, and Schar School colleagues Olzhas Zhorayev, Zifu Wang, and Meng-Hao Li, as well as Chaowei Yang, a professor in the Department of Geography and Geoinformation Science in the College of Science.
The study appears in the International Journal of Health Geographics.
Illegal organ trafficking is widely viewed by health experts as a major but poorly measured global crisis. More than 840 million people worldwide live with chronic kidney disease, and demand for transplants far exceeds supply. On average, only about 13.5 kidney transplants occur for every 255 patients who need one, according to the study. Long waiting times—sometimes up to five years—contribute to roughly seven percent of patients dying or leaving transplant lists annually.
To better understand the hidden market, the researchers analyzed more than 50,000 news articles published over 23 years. Using large language models and retrieval-augmented generation, they built what they describe as the first global, geospatial database of illegal kidney trafficking. The system identifies reported cases and assigns roles such as seller, buyer, broker and surgery location, while also tracing financial flows.
Their analysis reveals a stark global pattern. Kidney sellers most often come from lower-income or vulnerable countries including India, China, Pakistan, Nepal, Bangladesh, and Nigeria. Buyers, by contrast, are concentrated in wealthier nations—notably Israel, the United States, the United Kingdom, Canada, and Germany.
Illegal transplant surgeries most frequently occur in India, Pakistan, China, Sri Lanka, Turkey, Thailand, and Egypt, the researchers found. Brokers often operate in the same countries as sellers but also appear commonly in Western countries.
The network is fluid: About half of the countries playing major roles shift each decade due to factors such as conflict, legal changes, enforcement intensity, and corruption. One pattern, however, has remained consistent: Over the past two decades, the United States has stayed among the top three illicit kidney buyer countries, accounting for more than 7% of documented cases.
Unlike some countries that rely on narrow supply channels, U.S.-linked cases connect to a wide range of supplier nations, including Russia, Ukraine, Kazakhstan, and India—a pattern the researchers say points to structural demand pressures within wealthy health systems.
Financial data extracted in the study underscore the imbalance in the illicit market. Buyers typically pay between $50,000 and $120,000 for a kidney, while sellers often receive less than 10% of that amount. Most profits flow to brokers and organizers.
The authors say the new database enables systematic cross-country analysis that was previously impossible because evidence was fragmented and often limited to small regional studies. Future research will examine how illegal kidney prices and trafficking patterns relate to income levels, inequality, legal frameworks, and health care access.
More broadly, the researchers argue their work demonstrates how artificial intelligence can expose hidden global systems by converting scattered media reports into structured data. They say the findings could help policymakers target enforcement, strengthen international cooperation and better protect vulnerable populations.