CFTR and CFTR-related metabolic syndrome/CF screen positive, inconclusive diagnosis: CRMS/CFSPID is defined by an infant with a positive NBS result for CF and sweat chloride < 30 mmol/L and 2 CFTR mutations, at least one with an unclear phenotype OR an intermediate sweat chloride 30–59 mmol/L and 0 or 1 CF-causing mutations [40].