Normal sweat chloride test does not rule out cystic fibrosis

Başaran AE, Karataş-Torun N, Maslak İC, Bingöl A, Alper ÖM. Normal sweat chloride test does not rule out cystic fibrosis. Turk J Pediatr 2017; 59: 68-70. A 5-month-old patient presented with complaints of fever and cough. He was hospitalized with the diagnosis of bronchopneumonia and pseudo-Bartter's syndrome. Patient was further investigated for diagnosis of cystic fibrosis. The chloride (Cl) level in sweat was determined within the normal range (25.1 mmol/L, 20.3 mmol/L). CFTR (Cystic Fibrosis Transmembrane Regulator gene; NM_000492.2) genotyping results were positive for p.E92K; p.F1052V mutations. The patient was diagnosed with cystic fibrosis. In our patient, with features of CF and normal sweat test, mutation analysis was helpful for the diagnosis of cystic fibrosis.