Short- and Long-Term Biological Variation in Cardiac Troponin I Measured with a High-Sensitivity Assay: Implications for Clinical Practice
Short- and Long-Term Biological Variation in Cardiac Troponin I Measured with a High-Sensitivity Assay: Implications for Clinical Practice
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DOI：
10.1373/clinchem.2008.107391
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发表时间：
2009-01-01
影响因子：
9.3
通讯作者：
Wians, Frank
中科院分区：
文献类型：
--
作者：
Wu, Alan H. B.;Lu, Quynh Anh;Wians, Frank
背景技术背景：心肌肌钙蛋白I（cTnI）新一代商业检测试剂的检测限和精密度提高，降低了第99百分位数临界值，从而提高了阳性检测结果的频率。由于系列检测在解释低浓度时很重要，我们评估了cTnI在短期（小时）和长期（周）的生物学变化，并确定了cTnI的参考变化值（RCV）和个体指数（II）。为了评估短期和长期变化，我们收集了12名健康志愿者每小时4小时的血液，17名健康志愿者每隔一周一次，共8周，用高灵敏度测定法测定cTnI（检测限，0.2 ng/L），并计算分析CV、个体内CV、个体间CV和总CV（分别为CVA、CVI、CVG和CVT; CVT = CVA + CVI + CVG）以及II。由于轻微的右偏的数据，RCV计算与lognormal approach.Results：在一天内的CVA，CVI和CVG，值分别为8.3%，9.7%和57%，分别为15%，14%和63%，相应的日间值。日内和日间的IIs分别为0.21和0.39。对数正态日内RCV分别为46%和-32%，日间RCV分别为81%和-45%.结论：低II值表明基于人群的参考区间对解释cTnI值的有用性低于个体患者连续变化值。这一标准对于解释使用极高灵敏度测定法测量的低浓度cTnI升高患者的结果、胸痛患者（短期）的结果以及评价药物的心脏毒性（长期）尤为重要。(C)2008年美国临床化学协会
BACKGROUND: The improved detection limit and precision in new-generation commercial assays for cardiac troponin I (cTnI) have lowered the 99th-percentile cutoff value, yielding higher frequencies of positive test results. Because serial testing is important in interpreting low concentrations, we evaluated the biological variation of cTnI in both the short (hours) and long (weeks) terms and determined reference change values (RCVs) and the index of individuality (II) for cTnI.METHODS: To assess short- and long-term variation, we collected blood from 12 healthy votunteers hourly for 4 h and from 17 healthy individuals once every other week for 8 weeks, measured cTnI with a high-sensitivity assay (detection limit, 0.2 ng/L), and computed analytical, intraindividual, interindividual, and total CVs (CVA, CVI, CVG, and CVT, respectively; CVT = CVA + CVI + CVG) as well as the II. Because of the slight right-skewness of the data, RCVs were Calculated with a lognormal approach.RESULTS: Within-day CVA, CVI, and CVG, values were 8.3%, 9.7%, and 57%, respectively; the corresponding between-day values were 15%, 14%, and 63%. Within and between-day IIs were 0.21 and 0.39, respectively. Lognormal within-day RCVs were 46% and -32%, respectively; the corresponding between-day values were 81% and -45%.CONCLUSIONS: The low II indicates that population-based reference intervals are less useful for interpreting cTnI values than following serial changes in Values in individual patients. This criterion is particularly important for interpreting results from patients who show cTnI increases at low concentrations measured with very high-sensitivity assays, from patients presenting with chest pain (short term), and for evaluating drugs for cardiotoxicity (long term). (C) 2008 American Association for Clinical Chemistry