ABSTRACT
To establish a reliable cost-effective screening criterion for cystic fibrosis [CF] among underweight children suffering from frequent chest infections using the sweat chloride test [SCT]. In a cross-sectional study, 145 children with frequent chest infections were seen in the Pediatric Department at Prince Rashed Bin Al-Hassan Hospital, Irbid, Jordan, between January and December 2008. Their age ranged from 2-12 years [87 males and 58 females]. We obtained 11 children with positive polymerase chain reaction [PCR] for CF from hospital laboratory records, and 134 had no confirmed CF. Nutritional anthropometric assessment of weight-for-age and height-for-age based on the Centers for Disease Control and Prevention/World Health Organization 2000 was performed only on the confirmed 11 cases of CF. We used receiver operating curve statistical analysis to find the best SCT cut-off value for screening CF. The identification of CF is highly sensitive and specific when using the SCT >57 mmol/L. The sensitivity was 100% [95% confidence interval; 71.3-100%], specificity was 90.3% [95% confidence interval; 84-94.7%], and the good reliability Kappa statistical agreement beyond chance was 58.5%. A sweat chloride result of >57 mmol/L seems to strongly suggest the likelihood of CF, and should trigger further investigation in patients who have frequent respiratory symptoms and have failed to thrive