Kawasaki T, Ueno M, Uezono K, Kawazoe N, Nakamuta S, Ueda K, Omae T
Jpn Circ J. 1982 Sep;46(9):948-53. doi: 10.1253/jcj.46.948.
We assessed to what extent sodium intake can be estimated from the sodium content of a spot-urine specimen (spot-UNa) collected within 4 hours after the first voiding upon awakening but before breakfast. Subjects were asked to collect spot-urine and 24-hour urine specimens other than the spot-urine for a 3-day period, either successively or intermittently. The coefficient of correlation between spot-UNa and urinary excretion of sodium in 24 hours (24-h UNa) collected on the first day was 0.47. When the coefficient of the variation of creatinine excretion in the spot-urine was above 20%, the sample was discarded as the "outlier', and in this case the coefficient of correlation was 0.725. A marked fluctuation of creatinine excretion in spot-urine was considered to represent technical errors at the time of the spot-urine collection. The coefficient of variation of intra-individual 24-h UNa exceeded 20%, suggesting that a single determination of 24-h UNa does not represent the individual average of daily urinary excretion of sodium. It is concluded that the determination of a substantial number of spot-urine specimens to estimate daily salt ingestion of a given subject may be more reliable than a single determination of 24-h UNa, if the "outlier' of creatinine excretion in spot-urine specimen is excluded from the determination of spot-UNa. The average urinary excretion of sodium in 24 hours by the Japanese subjects investigated here was 218 +/- 67 mEq.
我们评估了从觉醒后首次排尿但早餐前4小时内收集的随机尿标本（随机尿钠）的钠含量来估计钠摄入量的程度。要求受试者在3天内连续或间断地收集随机尿和除随机尿外的24小时尿标本。第一天收集的随机尿钠与24小时尿钠排泄量（24小时尿钠）之间的相关系数为0.47。当随机尿中肌酐排泄变异系数高于20%时，该样本作为“异常值”被丢弃，此时相关系数为0.725。随机尿中肌酐排泄的明显波动被认为代表随机尿收集时的技术误差。个体内24小时尿钠的变异系数超过20%，这表明单次测定24小时尿钠并不能代表个体每日尿钠排泄的平均值。得出的结论是，如果在随机尿钠测定中排除随机尿标本中肌酐排泄的“异常值”，那么测定大量随机尿标本以估计特定受试者的每日盐摄入量可能比单次测定24小时尿钠更可靠。此处调查的日本受试者24小时尿钠平均排泄量为218±67 mEq。
