Table 1

Definitions of CRMS, CFSPID and the global harmonised designation CRMS/CFSPID

Newborn screenANDOR
CRMS (USA) [8]Asymptomatic infants with raised IRTPersistently intermediate sweat chloride# and fewer than two CFTR mutationsNormal sweat chloride (<30 mmol·L−1) and two CFTR mutations with zero or one CF causing
CFSPID (Europe) [2]Asymptomatic infants with raised IRTIntermediate sweat chloride (30–59 mmol·L−1) and zero or one CFTR mutationsNormal sweat chloride (<30 mmol·L−1) and two CFTR mutations, at least one of which has unclear phenotypic consequences
CRMS/CFSPID [3, 4, 11]Infants with a positive newborn screening testIntermediate sweat chloride (30–59 mmol·L−1) and zero or one CFTR variantsNormal sweat chloride (<30 mmol·L−1) and two CFTR variants with zero or one CF causing variants

#: 30–59 mmol·L−1 if <6 months or 40–59 mmol·L−1 if ≥6 months; : the term CFTR “variant” is now preferred to “mutation”, which was used originally [3]. Reproduced and modified from [5].