Table 3 Value of historical pointers in predicting specific cause of cough in children.

Historical pointer	Sensitivity (%)	Specificity (%)	NPV (%)	PPV (%)	LR
Moist cough	96	26	73	74	1.29
Duration >6 months	42	68	34	74	1.30
Exertional dyspnoea	38	65	32	70	1.06
Chronic dyspnoea†	7	97	32	83	2.25
Recurrent pneumonia*	7	94	31	71	1.12
Haemoptysis	7	97	32	83	2.25
Swallowing problems‡	25	71	30	65	0.85

NPV, negative predictive value; PPV, positive predictive value; LR, likelihood ratio.

*Defined as ⩾2 episodes of pneumonia in a year or ⩾3 episodes ever.

†Child appears short of breath as defined by parents' awareness of breathing and/or increased respiratory rate during period of the coughing illness.

‡Defined as coughing associated with swallowing liquids or solids one or more time/day throughout coughing illness.