Remer Thomas, Montenegro-Bethancourt Gabriela, Shi Lijie
DONALD Study Centre at the Research Institute of Child Nutrition, Department of Nutritional Epidemiology, Institute of Nutrition and Food Science (IEL), University of Bonn, Dortmund, Germany.
DONALD Study Centre at the Research Institute of Child Nutrition, Department of Nutritional Epidemiology, Institute of Nutrition and Food Science (IEL), University of Bonn, Dortmund, Germany.
Clin Biochem. 2014 Dec;47(18):307-11. doi: 10.1016/j.clinbiochem.2014.09.009. Epub 2014 Sep 17.
To examine the long-term stability and validity of analyte concentrations of 21 clinical biochemistry parameters in 24-h urine samples stored for 12 or 15 yr at -22°C and preservative free.
Healthy children's 24-h urine samples in which the respective analytes had been measured shortly after sample collection (baseline) were reanalyzed. Second measurement was performed after 12 yr (organic acids) and 15 yr (creatinine, urea, osmolality, iodine, nitrogen, anions, cations, acid-base parameters) with the same analytical methodology. Paired comparisons and correlations between the baseline and repeated measurements were done. Recovery rates were calculated.
More than half of the analytes (creatinine, urea, iodine, nitrogen, sodium, potassium, magnesium, calcium, ammonium, bicarbonate, citric & uric acid) showed measurement values after >10 yr of storage not significantly different from baseline. 15 of the 21 parameters were highly correlated (r=0.99) between baseline and second measurement. Poorest correlation was r=0.77 for oxalate. Recovery ranged from 73% (oxalate) to 105% (phosphate).
Our results suggest high long-term stability and measurement validity for numerous clinical chemistry parameters stored at -22°C without addition of any urine preservative. Prospective storage of urine aliquots at -22°C for periods even exceeding 10 yr, appears to be an acceptable and valid tool in epidemiological settings for later quantification of several urine analytes.
检测24小时尿液样本中21种临床生化参数的分析物浓度在-22°C无防腐剂条件下储存12年或15年的长期稳定性和有效性。
对健康儿童的24小时尿液样本进行重新分析，这些样本在采集后不久（基线）已对各自的分析物进行过测量。12年后（有机酸）和15年后（肌酐、尿素、渗透压、碘、氮、阴离子、阳离子、酸碱参数）采用相同的分析方法进行第二次测量。对基线测量值和重复测量值进行配对比较和相关性分析，并计算回收率。
超过半数的分析物（肌酐、尿素、碘、氮、钠、钾、镁、钙、铵、碳酸氢盐、柠檬酸和尿酸）在储存超过10年后的测量值与基线值无显著差异。21个参数中有15个在基线测量和第二次测量之间具有高度相关性（r = 0.99）。草酸盐的相关性最差，r = 0.77。回收率在73%（草酸盐）至105%（磷酸盐）之间。
我们的结果表明，在-22°C不添加任何尿液防腐剂的情况下，众多临床化学参数具有较高的长期稳定性和测量有效性。在流行病学研究中，将尿液等分样本在-22°C下前瞻性储存甚至超过10年，似乎是一种可接受且有效的工具，用于后期对多种尿液分析物进行定量分析。
