Nanoduct Sweat Conductivity Measurements in 2664 Patients: Relationship to Age, Arterial Blood Gas, Serum Electrolyte Profiles and Clinical Diagnosis

Abstract

Background: The Nanoduct device has acceptable diagnostic accuracy, but there is not enough systematic data supporting its usage in the diagnosis of cystic fibrosis (CF).

Methods: A retrospective review of patients with an indication for the sweat test was conducted. The conductivity test was repeated in patients who had values higher than 60 mmol/L, and they were referred for sweat chloride measurements. Associations between sweat conductivity measurements and age, gender, (pH, HCO₃, pCO₂, Na, K, Cl), family history, consanguinity, indications for the test and number of hospitalization were studied.

Results: Among 2,664 patients, 16 children had sweat conductivity values higher than 80. The median age of patients diagnosed with CF was 4 months old. Age, pH, HCO₃, Na, Cl, K and the sweat conductivity test were statistically related (P < 0.001). The ROC curve showed very high agreement between the 2nd conductivity test and the sweat test.

Conclusions: Patients suspected to have CF can be screened using the Nanoduct conductivity device in non-qualified centers.




doi: http://dx.doi.org/10.4021/jocmr1191w