Affiliations: [a] Research Centre on Aging, University of Sherbrooke, Sherbrooke, PQ, Canada | [b] Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, PQ, Canada
Correspondence:
[*]
Corresponding author: Eric D.B. Goulet, Research Centre on Aging/Faculty of Physical Activity Sciences, University of Sherbrooke, 1036 Belvédère Sud, Sherbrooke, Québec, J1H 4C4, Canada. Tel.: +1 819 821 8000 62728; Fax: +1 819 829 7141; E-mail:eric.goulet@usherbrooke.ca
Abstract:
BACKGROUND: The 24-h urine collection technique is the reference
method for assessing sodium intake. Frequent assessments of urinary sodium
excretion improve patients' motivation in adhering to sodium-restricted
diets. No portable, inexpensive, user-friendly and reliable sodium analyzers
are available on the market. Allowing field practitioners access to such an
instrument could facilitate patients' monitoring of urinary sodium output,
potentially improving patients care and overall population health. OBJECTIVE: To determine the validity and intra- and
inter-instruments reliability of two portable, easy-to-use and inexpensive
sodium analyzers. METHODS: Urine samples (N= 77) were collected from 31 men and
compared against reference values of an ion chromatograph. RESULTS: Both analyzers demonstrated excellent absolute (95%
limits of agreement (LoA) of ± 3-4%) and relative intra-instrument
reliability (intraclass correlation coefficients (ICC) of 1.00).
Inter-instruments relative reliability was excellent (ICC: 0.99), whereas
absolute reliability was good (95% LoA of ± 13%). Compared with
results obtained by ion chromatography, relative validity was excellent for
both analyzers. Absolute validity was good-to-moderate (95% LoAs ranging
from ± 15% to ± 20%). CONCLUSIONS: A low cost, portable analyzer can reliably be used by
field practitioners to monitor changes in urinary sodium excretion across
time and provide adequate guidance for individuals on sodium-restricted
diets.
