Quantitative Criteria for Tubulitis ("t") Score (assumes minimum sampling)
t0	No mononuclear cells in tubules
t1	Foci with 1 to 4 cells/tubular cross section or 10 tubular cells
t2	Foci with 5 to 10 cells/tubular cross section
t3	Foci with >10 cells/tubular cross section, or the presence of at least two areas of tubular basement membrane destruction accompanied by i2/i3 inflammation and t2 tubulitis elsewhere in the biopsy.

Quantitative Criteria for Mononuclear Cell Interstitial Inflammation ("i")
i0	No or trivial interstitial inflammation (<10% of unscarred parenchyma)
i1	10 to 25% of parenchyma inflamed cells
i2	26 to 50% of parenchyma inflamed
i3	>50% of parenchyma inflamed
Indicate presence of remarkable numbers (>10% of total cells) of eosinophils, polys, or plasma cells (specify which) with an asterisk on i

Quantitative Criteria for the Early Type of Allograft Glomerulitis ("g")
g0	No glomerulitis
g1	Glomerulitis in <25% of glomeruli
g2	Segmental or global glomerulitis in about 25 to 75% of glomeruli
g3	Glomerulitis (mostly global) in >75% glomeruli

Quantitative Criteria for Arteriolar Hyaline Thickening ("ah")
ah0	No PAS-positive hyaline thickening
ah1	Mild-to-moderate PAS-positive hyaline thickening in at least one arteriole
ah2	Moderate-to-severe PAS-positive hyaline thickening in more than one arteriole
ah3	Severe PAS-positive hyaline thickening in many arterioles
Indicate arteriolitis (significance unknown) by an asterisk on ah

Quantitative Criteria for Intimal Arteritis ("v")
v0	No arteritis
v1	Mild-to-moderate intimal arteritis in at least one arterial cross section
v2	Severe intimal arteritis with at least 25% luminal area lost in at least one arterial cross section
v3	Arterial fibrinoid change and/or transmural arteritis with medial smooth muscle necrosis with lymphocytic inflammation
Note number of arteries present and number affected. Indicate infarction and/or interstitial hemorrhage by an asterisk (with any level v score)

Quantitative Criteria for Allograft Glomerulopathy ("cg")
cg0	No glomerulopathy, double contours in <10% of peripheral capillary loops in most severely affected glomerulus
cg1	Double contours affecting up to 25% of peripheral capillary loops in the most affected of nonsclerotic glomeruli
cg2	Double contours affecting 26 to 50% of peripheral capillary loops in the most affected of nonsclerotic glomeruli
cg3	Double contours affecting more than 50% of peripheral capillary loops in the most affected of nonsclerotic glomeruli
Note number of glomeruli and percentage sclerotic

Quantitative Criteria for Interstitial Fibrosis ("ci")
ci0	Interstitial fibrosis tissue in up to 5% of cortical area
ci1	Mild- Interstitial fibrosis tissue in 6 to 25% of cortical area
ci2	Moderate- interstitial fibrosis of 26 to 50% of cortical area
ci3	Severe interstitial fibrosis of >50% of cortical area

Quantitative Criteria for Tubular Atrophy ("ct")
ct0	No tubular atrophy
ct1	Tubular atrophy in up to 25% of the area of cortical tubules
ct2	Tubular atrophy involving 26 to 50% of the area of cortical tubules
ct3	Tubular atrophy of >50% of the area of cortical tubules

Quantitative Criteria for Fibrous Intimal Thickening ("cv")
cv0	No chronic vascular changes
cv1	Vascular narrowing of up to 25% lumenal area by fibrointimal thickening of arteries ± breach of internal elastic lamina or presence of foam cells or occasional mononuclear cells*
cv2	Increased severity of changes described above with 26 to 50% narrowing of vascular lumenal area*
cv3	Severe vascular changes with >50% narrowing of vascular lumenal area*
* in most severely affected vessel. Note if lesions characteristic of chronic rejection (elastica breaks, inflammatory cells in fibrosis, formation of neointima) are seen

Quantitative Criteria for Mesangial Matrix Increase ("mm")*
mm0	No mesangial matrix increase
mm1	Up to 25% of nonsclerotic glomeruli affected (at least moderate matrix increase)
mm2	26-50% of nonsclerotic glomeruli affected (at least moderate matrix increase)
mm3	>50% of nonsclerotic glomeruli affected (at least moderate matrix increase)
* The threshold criterion for the moderately increased "mm" is the expanded mesangial interspace between adjacent capillaries. If the width of the interspace exceeds two mesangial cells on the average in at least two glomerular lobules the "mm" is moderately increased

References Solez K, et al. International standardization of criteria for the histologic diagnosis of renal allograft rejection: The Banff working classification of kidney transplant pathology. Kidney Int 1993;44(2):411-22. Solez K, et al. Report of the third Banff conference on allograft pathology (July 20-24, 1995) on classification and lesion scoring in renal allograft pathology. Trans Proc 1996;28(1):441-4. Racusen L, et al. The Banff 97 working classification of renal allograft pathology. Kidney Int 1999;55:713-723