A Study on Evaluating Solute Excretion in the Normal Neonate

Choi, Jeong Hoon; Kim, Mi Kyung; Yoo, Kee Hwan; Hong, Young Sook; Lee, Joo Won; Kim, Soon Kyum

J Korean Soc Pediatr Nephrol > Volume 4(1); 2000 > Article

J Korean Soc Pediatr Nephrol 2000;4(1): 6-10.

정상 신생아에서 용질배설 측정 의의에 관한 연구

최정훈, 김미경, 유기환, 홍영숙, 이주원, 김순겸

¹고려대학교 의과대학 소아과학 교실
²고려대학교 의과대학 소아과학 교실
³고려대학교 의과대학 소아과학 교실
⁴고려대학교 의과대학 소아과학 교실
⁵고려대학교 의과대학 소아과학 교실
⁶고려대학교 의과대학 소아과학 교실

A Study on Evaluating Solute Excretion in the Normal Neonate

Jeong Hoon Choi, Mi Kyung Kim, Kee Hwan Yoo, Young Sook Hong, Joo Won Lee, Soon Kyum Kim

¹Department of Pediatrics, Korea University, College of Medicine
²Department of Pediatrics, Korea University, College of Medicine
³Department of Pediatrics, Korea University, College of Medicine
⁴Department of Pediatrics, Korea University, College of Medicine
⁵Department of Pediatrics, Korea University, College of Medicine
⁶Department of Pediatrics, Korea University, College of Medicine

ABSTRACT

Purpose: To evaluate whether the urinary creatinine concentration is a reliable reference value to standardize urinary solute excretion in a spot urine sample during the first week of life.
Methods: Spontaneously voided urine specimens were obtained in 49 healthy full term neonates, and in 33 healthy older children with the median ages of $5.7{pm}4.3$ years, two urine samples were available with an interval of 2 to 3 days. Urine creatinine concentration was determined by the Jaffe test(CoBAS, Integra, Roche, Swiss). Uurine osmolality was determined by the freezing point depression test(Multi-osmette, Precision, USA).
Results : Mean urinary creatinine and osmolality values of the first urine samples were not significantly different with the second urine samples in each group. Mean urinary creatinine and osmolality values in neonates were significantly different from the older children of the each urine sample(P<0.01). In neonates, the mean of the urinary oreatinine/osmolality ratios was higher than that of the older children(P<0.01). The urinary creatinine and the creatinine/osmolality values of the first urine samples were closely correlated with those of the second samples in both two groups(P<0.001).
Conclusion : The urinary creatinine concentration during the first day of life is relatively stable, even when corrected for urinary osmolality The urinary creatinine and the urinary creatinine/osmolality ratio, therefore, can be used to standardize the urinary excretion of solutes in the neonate.

Key words: Neonate | Solute excretion | Urinary creatinine | Creatinine/osmolality ratio