1. At-home determination of 24-h urine sodium excretion: Validation of chloride test strips and multiple spot samples
- Author
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R.H. Lee, Brooke C.D. Hockin, Natalie Dawn Heeney, Shubhayan Sanatani, D.C. Clarke, Kathryn Armstrong, T. Sedlak, and Victoria E. Claydon
- Subjects
Male ,Sodium ,chemistry.chemical_element ,Urine ,Urinalysis ,Chloride ,Urine sodium ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Chlorides ,Sodium excretion ,medicine ,Humans ,Sodium Chloride, Dietary ,Morning ,24 h urine ,Chromatography ,Endocrine and Autonomic Systems ,Chemistry ,Chloride test ,Sodium, Dietary ,Neurology (clinical) ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Sodium intake and compliance with dietary sodium modification are typically assessed using a 24-h urine collection analyzed using flame photometry, but this is inconvenient. Spot urine samples have been investigated as alternatives to 24-h collections, but their accuracy is poor. Since sodium and chloride are present in equal concentrations in dietary salt, chloride test strips may provide a suitable proxy for at-home measurement of urine sodium concentrations. We aimed to determine whether (i) chloride test strips provide a reliable measure of urinary sodium compared to the gold standard flame photometry and (ii) multiple spot samples accurately reflect 24-h urine sodium. We recruited 43 participants (19 males) aged 23.6 ± 0.6 years to complete multiple consecutive spot samples (morning and evening) along with a 24-h urine sodium collection. Urine 24-h sodium estimates using chloride test strips (114.6 ± 7.5 mmol/day) were highly correlated (r = 0.900, p 0.0001) with flame photometry (121.1 ± 7.7 mmol/day) with a bias of -6.53 ± 22.2 mmol/day. Use of a three-spot sample average (both morning and evening spot samples) with a correction factor applied (122.9 ± 4.1 mmol/day) provided a good approximation of 24-h sodium measured by flame photometry (125.6 ± 9.0 mmol/day), with a bias of -2.55 ± 43.9 mmol/day. Chloride test strips applied to a 24-h urine collection provide a highly accurate measure of urinary sodium excretion, permitting convenient at-home sample collection and analysis. Their application to multiple spot samples provides a reasonable approximation of sodium excretion that can be used to conveniently monitor attempts at dietary sodium manipulation, without the inconvenience of completing a 24-h urine sample.
- Published
- 2020