Table 1

An example of how to use numbers in an Interpretation

Population	Pretest (background) probability of neuroblastoma (%)	Test result	Post-test probability of neuroblastoma (%)
Vague suspicion of neuroblastoma, non-specifically unwell child	2	Positive	63
	2	Negative	0
Secondary care, distinct suspicion of neuroblastoma	10	Positive	99
Secondary care, distinct suspicion of neuroblastoma	10	Negative	1
Paraspinal or renal mass, strongly suspected neuroblastoma	60	Positive	99.90
Paraspinal or renal mass, strongly suspected neuroblastoma	60	Negative	18
Unilateral Horner's syndrome	8	Positive	99
Unilateral Horner's syndrome	8	Negative	1
Well infants ∼6 months old, screening investigation	0.05	Positive	20
Well infants ∼6 months old, screening investigation	0.05	Negative	0.01
Opsoclonus-myoclonus syndrome	55	Positive	99.90
Opsoclonus-myoclonus syndrome	55	Negative	15

Reproduced from Erdelyi et al.2 Probability of patients in different clinical contexts having neuroblastoma based on positive and negative urine catecholamine and metabolite tests. Assumes average likelihood ratios (LR) for abnormal urine catecholamines of LR+ 85, LR− 0.15 (sensitivity ∼85% and specificity ∼99%).