Living kidney donation offers patients with kidney failure a viable treatment option. The selection process for a living donor is intentionally rigorous, prioritizing the well-being of the person giving the organ. The extensive medical and psychosocial screening ensures the donor is healthy enough to undergo major surgery safely. Furthermore, the evaluation confirms the donor can live a full life with only one remaining kidney, and that the decision to donate is voluntary and informed.
Conditions Directly Impacting Remaining Kidney Health
The selection process screens for any condition that could jeopardize the donor’s long-term health after the removal of one kidney. A major disqualifier is kidney dysfunction, often measured by the Glomerular Filtration Rate (GFR). GFR represents how effectively the kidneys filter waste from the blood. Most transplant centers require a GFR of 90 mL/min per 1.73 m² or greater to ensure sufficient reserve function remains in the single kidney. Potential donors with a GFR below 60 mL/min per 1.73 m² are typically not permitted to donate, as this indicates a reduction in renal capacity.
Uncontrolled high blood pressure, known as hypertension, can damage the small blood vessels within the kidneys over time. Transplant teams decline candidates whose hypertension has already caused evidence of target organ damage, such as changes to the eye’s vessels or the presence of protein in the urine. This sign of renal stress, known as significant proteinuria, is a common reason for exclusion, as it suggests an underlying disease process that could be accelerated by donation.
Diabetes Mellitus, both Type 1 and Type 2, is an absolute contraindication for living donation due to the high long-term risk of developing progressive kidney disease. Even if blood sugar is well-controlled, the disease causes long-term vascular damage that increases the risk of the remaining kidney failing. Other disqualifying conditions include a history of recurrent or bilateral kidney stones, which suggests a metabolic abnormality that could threaten the single kidney, or any current or history of cancer within the kidney itself.
Systemic Health Barriers to Major Surgery
Any active cancer or certain types of recent cancer can prevent donation, as the surgery may complicate treatment or the cancer indicates a reduced life expectancy. Cancers like melanoma or advanced lung cancer are often absolute exclusions, and a cancer-free waiting period of five or more years is typically required for other past malignancies. Severe cardiovascular disease represents another barrier, as the stress of major surgery and anesthesia increases the risk of heart attack or stroke.
Individuals with unstable angina, recent myocardial infarction, or severe congestive heart failure are generally excluded. Similarly, severe chronic lung diseases place the donor at elevated risk for breathing complications during and immediately following the operation.
Chronic and transmissible infections are also evaluated, as they pose a risk to both the donor and the recipient. While active infections generally require resolution before proceeding, criteria for conditions like Hepatitis B, Hepatitis C, and Human Immunodeficiency Virus (HIV) are rapidly evolving. Some centers now consider donation from individuals with well-controlled HIV or Hepatitis C to recipients who also have the same condition, but this is governed by specific institutional guidelines.
Psychological and Lifestyle Screening Criteria
Donors must be at least 18 years old to ensure they have the legal capacity to provide informed consent. While there is no strict upper age limit, older candidates often undergo more rigorous cardiac and general health testing to confirm their fitness for surgery, with some centers setting a practical limit around age 70.
Body Mass Index (BMI) criteria are used, as severe obesity complicates the surgical procedure and recovery. A BMI over 35 kg/m² is a common reason for automatic exclusion at many transplant centers, while those with a BMI between 30 and 35 may be encouraged to lose weight before the donation can proceed. This is necessary because obesity also increases the long-term risk of developing hypertension and diabetes, which further impacts the health of the single remaining kidney.
A psychological evaluation is mandatory to confirm the donor’s mental capacity and emotional readiness. Untreated or severe mental illnesses, such as active psychosis or major depression, may disqualify a donor if the condition impairs judgment or the ability to follow post-operative instructions. The evaluation also assesses for any history of drug or alcohol abuse, as current or recent substance use indicates a high risk for poor compliance with medical follow-up.
The most sensitive area of screening involves ensuring the decision is made without duress or improper financial incentive. Any evidence of coercion, pressure from the recipient or family members, or the expectation of financial gain beyond reimbursement for medical expenses will result in immediate disqualification. Transplant programs must confirm the donor’s motive is purely altruistic and that they understand the risks and benefits of the procedure, including the possibility of a negative psychological outcome if the transplant is unsuccessful.