Table 3.

Sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of seropositivity for RF by ELISA and anti-CCP antibodies in patients with very early inflammatory arthritis.

Diagnosis		RF ELISA Positive	Anti-CCP ELISA Positive	RF ELISA Positive and Anti-CCP ELISA Positive	RF ELISA Positive or Anti-CCP ELISA Positive
RA, n = 24	Persistent, n = 19	13	13	12	14
	Resolving, n = 5	2	2	2	2
Non-RA, n = 72	Persistent, n = 23	0	1	0	1
	Resolving, n = 49	4	0	0	4
RA (n = 24) vs	Sensitivity, %	63	63	58	67
Non-RA (n = 72)	Specificity, %	94	99	100	93
	PPV, %	79	94	100	76
	NPV, %	88	89	88	89
RA persistent	Sensitivity, %	68	68	63	74
(n = 19) vs other	Specificity, %	92	96	97	91
(n = 77)	PPV, %	68	81	86	67
	NPV, %	92	93	91	93