TABLE 1.

Component measures of the full and abbreviated iBOX.

iBOX component measures	Detailed information on the iBOX measures
Time of posttransplant risk assessment (fixed time points)	Phase 2/proof-of-concept iBOX assessment: 6 months
	Phase 3 iBOX assessment: 1 year, 2 years
Kidney function (eGFR and UPCR proteinuria)	eGFR, where eGFR is measured in mL/min/1.73 m2
	Log transformed (UPCR value a ), where UPCR is measured in gram per gram (g/g)
Immunological status (anti-HLA DSA MFI)	Anti-HLA DSA using a qualitative binary MFI cutoff
	• MFI <1,400 (References group)
	• MFI ≥1,400
Kidney damage assessment b (kidney allograft biopsy histopathology using Banff lesion scores)	Banff lesion score, interstitial fibrosis/tubular atrophy (IFTA score): Categorical variable with 3 levels
	• IFTA score = 0–1 (References group)
	• IFTA score = 2
	• IFTA score = 3
	Microcirculation inflammation (Banff lesion score, glomerulitis [g score] and Banff lesion score, peritubular capillaritis [ptc score]): Categorical variable with 3 levels
	• g and ptc score = 0–2 (References group)
	• g and ptc score = 3–4
	• g and ptc score = 5–6
	Banff lesion score, interstitial inflammation (i score) and Banff lesion score, tubulitis (t score): Categorical variable with 2 levels
	• i score and t score = 0–2 (References group)
	• i score and t score ≥3
	Banff lesion score, presence/extent of glomerular base membrane double contours; transplant glomerulopathy (cg score): Categorical variable with 2 levels
	• cg score = 0 (References group)
	• cg score = ≥1

DSA, donor-specific antibody; eGFR, estimated glomerular filtration rate; HLA, human leukocyte antigen; MFI, mean fluorescence intensity; UPCR, urine protein-to-creatinine ratio.

^a For proteinuria values below 0.05 g/g are replaced by 0.05 g/g before log-transformation.

^b Omitted from abbreviated iBOX.