Sodium assessment in neonates, infants, and children: a systematic review

Hyponatremia is a common disorder in childhood. The indirect and the direct potentiometry are currently the most popular techniques employed for sodium assessment, although discrepancies between the two techniques may be > 10 mmol/L. It is known that < 20% of the recently published articles report information about the technique used for sodium analysis, but no data are available on pediatric studies. This study aimed at investigating the laboratory technique employed for sodium measurement in studies conducted in childhood. A systematic literature search in PubMed, Embase, and Web of Science was undertaken to identify articles containing the word "hyponatremia" in the title between 2013 and 2020. Papers with < 10 subjects were excluded. A total of 565 articles were included. Information on the laboratory technique used for sodium analysis was more commonly (p = 0.035) reported in pediatric (n = 15, 28%) than in non-pediatric (n = 81, 16%) reports. The frequency of reports with and without information on the technique for sodium assessment was not different with respect to the study characteristics, the quartile of the journal where the paper was published, the country income setting, and the inclusion of neonates among the 54 pediatric studies.   Conclusion: Most pediatric papers do not report any information on the technique used for sodium analysis. Although international authorities have recommended the implementation of direct potentiometry, a low awareness on this issue is still widespread in pediatric research. What is Known: • Direct potentiometry and indirect potentiometry are currently employed for sodium analysis in blood. • Direct potentiometry is more accurate. What is New: • Less than 30% of pediatric articles provide information on the technique employed for sodium analysis in blood. • Indirect potentiometry is more frequently employed than direct potentiometry in pediatric studies.