TABLE 4.

Mean %dd-cfDNA in 280 biopsies grouped by DSA status

Biopsy groups (AMR and mixed are bold)	Geometric mean %dd-cfDNA			P DSA-negative vs DSA-positiveb
	DSA-negative (N = 220)	DSA-positivea(N = 60)	All (N = 280)
MMDx diagnoses
No rejection	0.31	0.40	0.32	0.40
Possible TCMR	0.20	–	0.20	–
TCMR	0.36	3.78	0.65	0.0004 (only 5 DSA-positive TCMR)
Possible AMR	0.45	0.76	0.53	0.60
AMR	1.77	2.11	1.90	0.55
Mixed (AMR + TCMR)	1.77	1.88	1.83	0.90
All AMR (including mixed)	1.77	2.04	1.88	0.56
Automated rejection (K1208) archetype
No rejection	0.31	0.49	0.33	0.18
TCMR1 (many mixed)	2.28	2.71	2.51	0.83
TCMR2	0.39	2.46	0.66	0.005
Early AMR	1.57	1.84	1.64	0.74
Full AMR	2.29	2.08	2.17	0.79
Late AMR	0.34	0.52	0.36	0.33
All AMR (including mixed)	1.22	1.94	1.46	0.08
Histology
No rejection	0.29	0.28	0.29	0.93
Possible TCMR	0.33	1.63	0.35	Only 1 DSA-positive pTCMR
TCMR	0.76	1.23	0.85	0.34
Possible AMRc	0.82	1.97	1.19	0.11
AMR	1.11	1.41	1.24	0.49
Mixed (AMR + TCMR)	1.82	3.00	2.38	0.41
All AMR (including mixed)	1.25	1.74	1.47	0.27
Inadequate	1.08	–	1.08	–
Missing	0.38	0.77	0.48	0.59

Bolding indicates rows with AMR and Mixed rejection, bolding and underlining indicate rows with all AMR.

^aIncludes panel-reactive antibody–high risk (PRAHR) biopsies. Biopsies from PRA-positive patients with missing/unavailable donor phenotyping to assign DSA status were called PRAHR in this study and were analyzed as DSA-positive.

^bTwo-tailed Welch t tests on logged %dd-cfDNA values.

^cTransplant glomerulopathy was included in possible AMR.

AMR, antibody-mediated rejection; dd-cfDNA, donor-derived cell-free DNA; DSA, donor-specific antibody; MMDx, Molecular Microscope Diagnostic System; PRA, panel-reactive antibody; TCMR, T cell–mediated rejection.