Table 2.

Cross classification of participants with chronic kidney disease by the various formulae and the kappa statistic for each comparison

	CKD-EPI cystatin C		CKD-EPIcr-cys		Cockcroft-Gault		MDRD
	yes	no	yes	no	yes	no	yes	no
CKD-EPI creatinine
yes	21	16	22	15	17	20	37	0
no	29	1026	42	1013	5	1050	5	1050
Kappa	0.462		0.410		0.565		0.934
CKD-EPI cystatin C
yes			47	3	16	34	21	29
no			17	1025	6	1036	21	1021
Kappa			0.815		0.429		0.433
CKD-EPIcr-cys
yes					16	48	23	41
no					6	1022	19	1009
Kappa					0.353		0.406
Cockcroft-Gault
yes							17	5
no							25	1045
Kappa							0.519

Number of participants with chronic kidney disease (CKD): CKD-EPI creatinine: n = 37; CKD-EPI cystatin C: n = 50; CKD-EPI creatinine-cystatin C (CKD-EPIcr-cys): n = 64; Cockcroft-Gault: n = 22; Modification of Diet in Renal Disease (MDRD): n = 42