The value of sweat chloride test in the diagnosis of cystic fibrosis among jordanian children

Abstract EN

Objective: To determine the frequency of cystic fibrosis by measurement of sweat chloride concentration among Jordanian children referred to Princess Iman Research and Laboratory Sciences Center, King Hussein Medical Center with a high index of suspicion of cystic fibrosis on clinical ground. Methods: About 1565 patients highly suspected of having cystic fibrosis were tested for sweat chloride using the Wescor Macroduct collecting system and Sweat Chick 3100. Results: One hundred fifty-three out of 1565 patients (9.8%) were found to have sweat chloride > 60 mmol/1, 132 (8.4%) had sweat chloride 45-59 mmol/1.

The false positive rate was 3% on test repetition and the false negative rate was 3.4%. Thirty seven percent of our patients presented with failure to thrive, diarrhea and chronic chest infection, 26% presented with either failure to thrive or short stature and the rest of patients had a wide spectrum of clinical presentation. Conclusion: Sweat chloride test is a very good screening and diagnostic tool.

There is a high percentage of patients with intermediate sweat chloride concentration where the diagnosis is equivocal and thus a genetic study to establish the diagnosis should be carried out.