From the Research
The highest number of kidneys a human can have, including transplant patients with end-stage renal disease (ESRD) requiring kidney transplantation, is theoretically up to six, considering the two native kidneys and the potential for multiple transplanted kidneys. This scenario can occur in patients who undergo multiple kidney transplants without having their failed kidneys removed, a common practice due to the added surgical risk and complexity of removing native kidneys 1, 2, 3.
Key Considerations
- The approach of leaving failed kidneys in place unless they cause complications is preferred to minimize surgical risk and complexity.
- Subsequent transplants can be placed in the abdomen, potentially resulting in a patient having multiple kidneys.
- The practice of not removing failed kidneys explains how some patients accumulate multiple kidneys throughout their transplant journey.
- Each additional kidney transplant becomes more challenging due to scar tissue and limited space in the abdomen.
Evidence Overview
The provided studies primarily focus on aspects of kidney transplantation, immunosuppressive therapy, and the management of end-stage renal disease, rather than directly addressing the maximum number of kidneys a human can have 1, 2, 3, 4, 5. However, they collectively support the understanding that multiple kidney transplants are feasible and that the native kidneys are often left in place, which can lead to a scenario where a patient has more than two kidneys.
Clinical Implications
In real-life clinical practice, the decision to remove or leave native kidneys during transplantation is made based on the individual patient's condition and the potential risks and benefits associated with the procedure. The accumulation of multiple kidneys in a patient, while theoretically possible, is a complex issue that depends on various factors, including the patient's overall health, the reason for the transplants, and the surgical approach used.
Recommendation
Based on the available evidence and clinical considerations, the maximum number of kidneys a human can have, including transplant patients, is up to six. This recommendation prioritizes the understanding of kidney transplantation practices and the potential for multiple transplants without native kidney removal, aligning with the goal of minimizing morbidity, mortality, and optimizing quality of life for patients with end-stage renal disease.