The Reliability of a Novel Automated System for ANA Immunofluorescence Analysis in Daily Clinical Practice

Table 4

Diagnostic performance of automated indirect immunofluorescence ANA detection in comparison to visually obtained results by 2 individual examiners utilizing 2 different assays. Crosstabulation of the diagnostic performance of the automated versus visual analyses by individual examiners of antinuclear antibodies (ANA) by indirect immunofluorescence (IIF) for all 336 serum samples and the subset of 89 that revealed a positive result by visual interpretation of the ANA-IIF-assay 2 (NEG: negative; AMB: ambiguous; POS: positive).

Comparison to the gold standard, derived by visual evaluation of assay 2 by 3 examiners	Automated analyses	Visually by examiner 1	Visually by examiner 2	Visually by examiner 1	Visually by examiner 2
	Assay 2	Assay 2	Assay 2	Assay 1	Assay 1
By category (): NEG, AMB, or POS
Concordance (%)	52	86	86	80	78
Kappa	0.34	0.75	0.75	0.59	0.55
By category (): NEG or POS (AMB = NEG)
Concordance (%)	90	93	94	91	90
Sensitivity (%)	75	87	89	70	65
Specificity (%)	96	96	96	99	99
Kappa	0.74	0.83	0.85	0.75	0.71
By titre ()
Concordance (%)	61	69	72	27	21
Kappa	0.55	0.63	0.66	0.15	0.10
By pattern ()
Concordance (%)	36	76	69	47	46
Kappa	0.28	0.67	0.52	0.33	0.32