Feasibility of Measuring Sodium, Potassium and Creatinine From Urine Sample Dried on Filter Paper

Abstract

Aim: To develop a bioassay for estimation of sodium, potassium and creatinine in dried urine strips and comparing with their respective concentration in liquid urine samples. Materials & methods: Urine was collected on filter paper strips, dried at room temperature and, eluted for estimation of sodium, potassium by indirect ion selective electrode method and creatinine by Jaffé method. Result: This bioassay was validated based on the US FDA guidelines for bioanalytical method validation and was linear, sensitive, accurate and precise with acceptable recovery and matrix effects. Analytes were stable in dried urine strips during 1 year of storage at 4°C. Conclusion: We conclude that the dried urine is suitable for analysis of sodium, potassium and creatinine and offers a convenient alternative for monitoring dietary salt intake.

Keywords:

• cardiovascular disease
• dried urine strip
• electrolytes
• hypertension
• kidney dysfunction
• salt intake

Acknowledgments

Authors would like to thank the participants and team members who took part of this study.

Financial & competing interests disclosure

Authors thank the Indian Council of Medical Research and WHO for providing financial support for National NCDs Monitoring Survey from which this pilot study was carried out. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The institutional review board of All India Institute of Medical Sciences, New Delhi, India approved the study. Informed consent was obtained from the all participants prior to conduct of the study.

Author contributions

M Tarik and R Lakshmy were involved in the design of experiment, data analysis, statistical analysis and the writing of the manuscript. A Ritvik, HR Salve, A Krishnan contributed toward recruitment of the participants for the study and evaluation of manuscript. P Mathur and P Joshi contributed in evaluation of manuscript.

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: https://www.tandfonline.com/doi/suppl/10.2144/000112170