Table 3. Subgroup analysis for the pertussis-tested cohort.

	Pertussis positive n = 12	Pertussis negative n = 59	p-value
Confirmatory test
Culture only	2	15	n/a
PCR only	5	31	n/a
PCR + culture	5	13	n/a
WBC	23.6 ± 13.3	12.6 ± 5.2	< 0.001
Lymphocyte	16.8 ± 9.7	7.9 ± 3.8	< 0.001


WBC: white blood cells; PCR: polymerase chain reaction; n/a: non-applicable. Values expressed as mean±standard deviation.