Generally referred to as “CF-related metabolic syndrome (CRMS)” in the US and “CF Screen Positive Inconclusive Diagnosis (CFSPID)” in Canada and Europe, these classifications describe infants with a positive CF newborn screen and either (1) a sweat chloride value < 30mmol/L and two CFTR mutations, at least one of which has unclear phenotypic consequences, or (2) an intermediate sweat chloride value (30–59 mmol/L) and one or zero CF-causing mutations [7,8]. The gene discussed is CFTR; the disease is cystic fibrosis.