Background: Malnutrition is a common problem in patients with cancer, especially in cases of non-hematologic malignancy. Twenty-four-hour urine urea nitrogen [UUN] can be used to assess nitrogen balance, which may indicate nutritional status. However, the procedure can be inconvenient. The use of spot urine samples is proposed as an alternative method of estimating 24-hour UUN.
Objective: To study the correlation between 24-hour UUN and UUN values from spot urine samples in patients with nonhematologic malignancy.
Materials and Methods: Twenty-nine patients with non-hematologic malignancy, who were admitted between January 2016 and March 2017, were enrolled in our study. Spot urine samples were taken from patients’ first void in the morning, after lunch, and from the last void on the same day. The correlation between both UUN and urine urea creatinine ratio [UUN/UCr] from spot urine samples and 24-hour UUN was analyzed using determining the Pearson correlation coefficient.
Results: The mean 24-hour UUN of the 29 patients who were enrolled was 4.87 g. The mean UUN of spot urine samples
from the morning, afternoon, and the last void were 394, 342, and 389 mg/dl, respectively. There were significant correlations between 24-hour UUN and UUN from spot urine samples taken from all time frames (p<0.001 for the morning sample, p = 0.001 for the afternoon sample, p = 0.01 for the last void sample). Additionally, correlation between 24-hour UUN and UUN/Cr from morning spot urine was also significant (p = 0.02).
Conclusion: The UUN from spot urine samples were significantly correlated with 24-hour UUN. Therefore, UUN from spot urine, particularly samples taken from the first void, may be used as a nutritional assessment tool, indicating protein metabolism, in patients with non-hematologic malignancy.

Keywords: Urine urea nitrogen, Urine urea to creatinine ratio, Spot urine sample, Cancer, Malnutrition