What tests are conducted for a potential living kidney donor and what do the results indicate?

Comprehensive Testing for Potential Living Kidney Donors

Living kidney donor candidates undergo extensive medical, psychological, and anatomical testing to ensure both donor safety and optimal recipient outcomes. 1

Blood and Compatibility Testing

• Blood type (ABO) testing must be performed twice to prevent incompatible transplantation 1
• HLA typing for Class I (A, B, C) and Class II (DP, DQ, DR) antigens to assess compatibility with intended recipient 1
• Cross-matching to detect donor-specific antibodies in the intended recipient 1
• Blood group A subtyping when donation is planned to recipients with anti-A antibodies 1

Kidney Function Assessment

• 24-hour urine collection to measure creatinine clearance (preferred over estimated formulas) 1
• Urinalysis to detect:
  • Proteinuria (confirmed with 24-hour collection) 1
  • Microscopic hematuria (requires ruling out contamination, UTIs, stones) 1
  • Microscopic pyuria 1

Imaging Studies

• CT angiogram or MRI/MRA to evaluate:
  • Renal parenchyma for abnormalities (atrophy, scarring, cysts) 1
  • Vascular anatomy (multiple vessels, atherosclerotic disease, fibromuscular dysplasia) 1
  • Collecting system abnormalities 1
  • CT is preferred for detecting calcifications and defining renal vein anatomy 1

Cardiovascular Assessment

• Blood pressure measurements (should be <140/90 mmHg in office or <135/85 mmHg on ambulatory monitoring) 1
• Cardiac stress testing indicated for:
  • Men ≥45 years or women ≥55 years 1
  • History of smoking 1
  • Family history of premature coronary artery disease 1
  • Dyslipidemia 1
  • Hypertension 1
  • Abnormal ECG 1

Metabolic Screening

• Fasting plasma glucose (diabetes is an absolute contraindication) 1
• Oral glucose tolerance test if indicated 1
• Lipid panel 1

Infectious Disease Screening

• HIV, hepatitis B and C (positive results generally contraindicate donation) 1, 2
• Syphilis (RPR) testing 1, 2
• CMV and EBV status 2, 3
• PPD skin test for tuberculosis (especially for those from endemic areas) 1, 2

Cancer Screening (Age-Appropriate)

• Colorectal cancer screening starting at age 50 1
• Breast cancer screening starting at age 40 1
• Cervical cancer screening starting at age 18 1
• Prostate cancer screening starting at age 50 (age 45 for African Americans or those with family history) 1

Pulmonary Assessment

• Pulmonary function testing if history suggests lung disease 1
• FEV1 or FVC should be >70% of predicted 1

Genetic/Familial Disease Screening

• For potential donors related to recipients with genetic kidney diseases:
  • Autosomal dominant polycystic kidney disease (ADPKD) screening 1
  • Thin basement membrane disease evaluation 1
  • Systemic lupus erythematosus screening (ANA, complement levels) 1
  • Familial glomerulonephritis assessment 1
  • Genetic testing when appropriate 1

Psychological Evaluation

• Assessment of motivation and understanding of risks 1
• Evaluation for coercion or financial incentives 1
• Discussion of possible psychological outcomes (benefits vs. depression/resentment) 1

What Test Results Mean

• Normal results: Candidate may proceed with donation if all criteria are met 1
• Abnormal kidney function: Donation is contraindicated if GFR is inadequate for age or proteinuria is present 1
• Abnormal imaging: Contraindications include significant renal atrophy, cortical scarring, multiple cysts, angiomyolipoma, significant atherosclerotic disease, or fibromuscular dysplasia 1
• Metabolic abnormalities: Known diabetes, FPG ≥126 mg/dL, or 2-hour glucose ≥200 mg/dL contraindicate donation 1
• Hypertension: Evidence of organ damage is an absolute contraindication; hypertension should be well-controlled with fewer than two medications 3
• Infectious disease: Positive HIV or hepatitis C results contraindicate donation 1, 2
• BMI >35: Generally contraindicated, especially with other comorbidities 1, 3

Common Pitfalls in Donor Evaluation

• Inadequate timing of infectious disease testing may miss infections in incubation period 2
• Overlooking family history of kidney disease in younger donors 1
• Failing to perform appropriate genetic testing in donors with family history of hereditary nephropathy 1
• Neglecting psychological assessment and preparation 1, 4
• Inadequate evaluation of vascular anatomy leading to surgical complications 1

Post-Donation Follow-Up

• Annual medical evaluation recommended 1
• Blood pressure monitoring (maintain <130/80 mmHg) 1
• Routine chemistry tests and urinalysis 1
• Avoidance of nephrotoxic medications 1
• Maintaining healthy lifestyle (regular exercise, avoiding high-protein/high-salt diets) 1