Sensitivity and specificity of single IgA and IgG antibody concentrations for early diagnosis of pertussis in adults: an evaluation for outbreak management in public health practice

Table 3 Specificities in external controls (n = 4275) and sensitivities in time intervals in reference to the onset of cough in pertussis cases (n = 46) of single IgA and IgG concentrations (see Figure 2). Geometrical Mean Concentrations (GMC) and number of samples are indicated.

Level (U/ml)^a	Specificity external controls	Sensitivity (%) in time intervals with reference to the onset of cough
		-21 to 0 days	1 to 14 days	15 to 21 days	22 to 87 days	1 to 87 days
IgA
24	90.0%	33	100	100	97	98
40	95.0%	33	63	82	95	90
52	97.5%	17	63	82	92	88
74	99.0%	17	63	64	78	75
GMC (U/ml)		11	60	136	212	177
IgG
27	90.0%	33	75	100	97	95
41	95.0%	33	75	91	95	93
65	97.5%	33	50	82	94	87
90	99.0%	33	38	82	86	81
100^b	99–100%	33	38	82	84	80
GMC (U/ml)		8	48	390	506	391
No. samples		6	8	11	64	83

^a Levels are obtained from the estimation of optimal cut-off values in Figure 2.
^b Used by the National Institute for Public Health and the Environment in The Netherlands for surveillance.

ISSN: 1471-2334