Association between 24-h Urine Urea Nitrogen and Spot Urine Collection
Sureerat Watcharasuwanseree1, Sornwichate Rattanachaiwong2, Pranithi Hongsprabhas2, Veeradej Pisprasert2
Affiliation : 1 Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand, 2 Division of Clinical Nutrition, Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
Objective: The 24-h urine urea nitrogen (UUN) is the standard measurement for nitrogen balance determination, but may be
impractical in certain situations. The authors aimed to estimate the correlation between the urine urea nitrogen to urine creatitine (UUN/UCr) ratio from spot urine samples and 24-h urine urea nitrogen.
Materials and Methods: The cross-sectional study enrolled patients admitted to internal medicine wards, Srinagarind Hospital, Khon Kaen University, Thailand, in 2016. Spot urine samples were taken periodically on the same day for 24-h urine collection.
Results: The respective median 24-h UUN, UUN/UCr for spot urine samples from the morning, before noon, and the last void for 34 patients was 4.75 g, 7.53, 6.60, and 7.48. Significant correlations were found between the 24-h UUN and UUN/UCr ratio from spot urine samples for all collection time frames. The UUN/UCr ratio from the sample before noon had the strongest correlation with 24-h UUN (R2=0.48). The 24-h UUN might be estimated from spot urine samples taken before noon by the equation: 24-h UUN = 0.78 (UUN/UCr from spot urine) +2.6.
Conclusion: The UUN/UCr ratio of a spot urine sample may be an alternative measurement when a 24-h sample is unavailable.
doi.org/10.35755/jmedassocthai.2021.S04.00041
Keywords : Urine urea nitrogen; Urine urea nitrogen to creatinine ratio; Spot urine sample; Non-critical illness; Protein
