Table 3. Number of laboratory-confirmed pertussis cases with information on the diagnostic method used for confirmation of pertussis, Denmark, 2010–13 (n = 13,269).

Age group	Method	2010		2011		2012		2013
		n	%	n	%	n	%	n	%
0 years	Culture	4	6	3	5	7	6	0	0
	PCR	64	93	58	95	120	94	64	100
	Serology	1	1	0	0	0	0	0	0
1–7 years	Culture	2	4	2	3	3	2	1	1
	PCR	46	94	56	92	166	95	73	91
	Serology	1	2	3	5	5	3	6	8
8–19 years	Culture	8	6	4	3	4	1	2	2
	PCR	118	86	94	76	216	71	96	73
	Serology	12	9	25	20	83	27	33	25
20–29 years	Culture	3	4	3	3	6	2	0	0
	PCR	51	61	66	73	152	57	98	66
	Serology	29	35	22	24	110	41	50	34
≥ 50 years	Culture	2	6	3	8	3	3	0	0
	PCR	20	61	18	50	54	51	30	48
	Serology	11	33	15	42	49	46	33	52
Total	Culture	19	5	15	4	23	2	3	1
	PCR	299	80	292	78	708	72	361	74
	Serology	54	15	65	17	247	25	122	25

Percentages show the contribution of each method for each year.