Home sodium monitoring in patients with diabetes insipidus

OBJECTIVE: To determine whether home care givers can accurately measure plasma sodium in children with diabetes insipidus (DI) by using an I-STAT portable clinical analyzer (PCA) and to collect preliminary data on home PCA use. STUDY DESIGN: Care givers of 4 children with DI and impaired thirst or inability to access water freely were instructed in PCA use. During an initial preclinical phase, the accuracy of sodium concentration measured by care givers was assessed by comparison to simultaneous analysis in a clinical laboratory. Participants were subsequently randomly assigned to daily home PCA monitoring or routine care. All participants crossed over from their original randomized group assignment to the alternate group. RESULTS: After a single education session, all care givers were able to perform PCA testing. There was good correlation between PCA and laboratory sodium (r = 0.92). On the basis of Error Grid Analysis, use of the PCA sodium would have resulted in treatment decisions identical to those made based on the laboratory sodium value in 62 of 66 instances. Four minor differences in treatment would have occurred. There was no statistically significant difference in clinical outcome during daily monitoring versus routine care. CONCLUSIONS: Results obtained by care givers using the PCA are sufficiently reliable for assessment of fluid status and making treatment decisions.