The assessment of population salt intake underpins the implementation of salt reduction policies. This study conducted a systematic review comparing 24h urine sample collections to spot urine samples and overnight urine samples to aid efficient assessment.

MEDLINE and EMBASE were searched for papers that included both 24h and spot or timed urine sodium collections and analyses and the total number fitting the inclusion criteria and after discarding the duplicates were 44. After reading the papers, four children studies and sixteen adult studies were found to fit the criteria for the systematic review. Three of the four children studies included in this review validated the use of overnight sampling of urine to estimate sodium levels instead of collecting 24h samples. All sixteen adult studies also validated the use of partial sampling-whether the comparison was made between overnight urine collection or spot sampling collection versus the 24h urine collections.