Table 1 Demographics and characteristics.

Values are reported in the given units with SD in parentheses, and all comparisons between groups were nonsignificant. Recipients are both adult (>18 years) and pediatric (≤18 years) in each cohort. Clinical pathology data are based on the day of biopsy, which is timed with the urine collection, which occurred before performance of the biopsy. ABMR/TCMR split is of AR-confirmed patients, based on the Banff allograft pathology classification (17). All other demographic and clinical information is based on the day of the kidney transplant.

Phenotype characteristicTraining
(n = 111)
Validation #1
(n = 103)
Validation #2
(n = 59)
Recipient
  Recipient age, year (SD)29 (13.4)32 (14.2)32 (11.7)
  Recipient male/female (%)48/5249/5142/58
Donor
  Donor age, year (SD)35 (12.4)36 (14.4)39 (10.0)
  Donor male/female (%)43/5744/5640/69
Ethnicity (%)
  Caucasian353948
  Hispanic322521
  Asian262724
  African American322
  Other475
Donor source (%)
  Deceased49.442.455%
Clinical pathology
  AR/STA39/7232/7132/27
  ABMR/TCMR (of AR)24/159/235/27
Cause of ESRD (%)
  Obstructive545
  Diabetes202218
  Hypertension433742
  Glomerulonephritis877
  Immune-mediated202324
  Congenital542
  Other152