Table 4

Summary of subjects with discrepant diagnostic outcomes due to sweat chloride concentrations of 30–39 mmol/litre

Phenotype	Sweat chloride (mmol/litre)	Genotype		NPD (mV): ΔCl-free+Iso	American guideline (without and with NPD)	European guideline
PANC	30	DF508	D1152H	8	Unlikely CF	CFTR dysfunction
AZOOSP	30	G542X	R117C	−6	Unlikely CF	CFTR dysfunction
AZOOSP	31	R117H(7T)	R117H(7T)	−5	Unlikely CF	CFTR dysfunction
PANC	31	DF508	3849+10 kb C>T	2	CF	CFTR dysfunction
AZOOSP	32	W1282X	–	−6	Unlikely CF	CFTR dysfunction
AZOOSP	36	G542X	5T	−6	Unlikely CF	CFTR dysfunction
PANC	38	W1282X 5T	5T	−1	Unlikely CF	CFTR dysfunction
AZOOSP	38	A198P	–	−5.4	Unlikely CF	CFTR dysfunction
PANC	39	DF508	R75Q	−3	Unlikely CF	CFTR dysfunction
RESP	39	DF508	L967S	−6	Unlikely CF	CFTR dysfunction

Change in CFTR-mediated chloride diffusion following perfusion with a chloride-free solution and isoproterenol (ΔCl-free+Iso): normal (<−12 mV), intermediate (−12 to −7.7 mV) and abnormal (>−7.7 mV).
AZOOSP, obstructive azoospermia; CF, cystic fibrosis; CFTR, cystic fibrosis transmembrane conductance regulator; NPD, nasal potential difference; PANC, idiopathic recurrent acute or chronic pancreatitis; RESP, idiopathic sinopulmonary disease.