Mårtensson J, Groth S, Rehling M, Gref M
Department of Clinical Physiology, Norrlands University Hospital, Umeå, Sweden.
J Nucl Med. 1998 Dec;39(12):2131-7.
In 1996, a committee on renal clearance recommended a mean sojourn time-based methodology for single-sample determination of plasma clearance of 99mTc-diethylenetriamine pentaacetic acid (DTPA) to be used on adults if the patient's glomerular filtration rate (GFR) is suspected to be >30 ml/min. The main purpose of this study was to derive a mean sojourn time-based formula for calculation of 51Cr-ethylenediamine tetraacetic acid (EDTA) clearance in adults.
Two groups of patients with 51Cr-EDTA clearance (Cl) between 16 and 172 ml/min were studied. In Group I (n = 46), reference Cl was determined as a multiplasma sample, single-injection method (ClSM). Sixteen blood samples were drawn from 0 until 5 hr after a single intravenous injection of 51Cr-EDTA. In Group II (n = 1046), reference Cl was determined by the Brøchner-Mortensen four-sample clearance method (ClBM). The plasma time-activity curves of Group I were used to derive two mean sojourn time-based formulas (Formulas 1 and 2) for calculation of a single-sample clearance. Formula 1 was derived from the entire time-activity curve, whereas the derivation of Formula 2 used only the final slope of the time-activity curve. The accuracy of the two formulas and the Christensen and Groth 99mTc-DTPA formula was tested on Group II.
Chromium-51-EDTA Cl calculated by Formula 1 was almost identical to the Cl calculated by the reference Cl method (r = 0.982; SDdiff = 5.82 ml/min). Both 51Cr-EDTA Cl calculated by Formula 2 and by the 99mTc-DTPA formula showed close correlation with the reference method (r = 0.976, r = 0.985, respectively) but systematically overestimated GFR for the whole range of clearance values by 3.5 and 3.2 ml/min (p<0.001), respectively.
It is possible to get an accurate determination of 51Cr-EDTA Cl from a single-plasma sample in adults by the mean sojourn time methodology. The determination is marginally more accurate (p<0.001) if using a formula derived from the entire plasma time-activity curve than from only the final slope. The single-sample formula derived for determination of 99mTc-DTPA Cl tends slightly to overestimate GFR if used to calculate 51Cr-EDTA Cl.
1996年，一个肾脏清除率委员会推荐了一种基于平均滞留时间的方法，用于在怀疑患者肾小球滤过率（GFR）>30 ml/min时，对成人进行99mTc-二乙三胺五乙酸（DTPA）血浆清除率的单样本测定。本研究的主要目的是推导一个基于平均滞留时间的公式，用于计算成人的51Cr-乙二胺四乙酸（EDTA）清除率。
研究了两组51Cr-EDTA清除率（Cl）在16至172 ml/min之间的患者。在第一组（n = 46）中，参考Cl通过多血浆样本单注射法（ClSM）测定。在单次静脉注射51Cr-EDTA后0至5小时内采集16份血样。在第二组（n = 1046）中，参考Cl通过布罗克纳-莫滕森四样本清除率法（ClBM）测定。第一组的血浆时间-活性曲线用于推导两个基于平均滞留时间的公式（公式1和公式2），用于计算单样本清除率。公式1从整个时间-活性曲线推导得出，而公式2的推导仅使用时间-活性曲线的最终斜率。在第二组中测试了这两个公式以及克里斯蒂安森和格罗思的99mTc-DTPA公式的准确性。
用公式1计算的51Cr-EDTA Cl与参考Cl方法计算的Cl几乎相同（r = 0.982；SDdiff = 5.82 ml/min）。用公式2和99mTc-DTPA公式计算的51Cr-EDTA Cl与参考方法均显示出密切相关性（分别为r = 0.976，r = 0.985），但在整个清除率值范围内，系统性地高估GFR分别为3.5和3.2 ml/min（p<0.001）。
通过平均滞留时间方法，可以从成人的单份血浆样本中准确测定51Cr-EDTA Cl。如果使用从整个血浆时间-活性曲线推导的公式，而不是仅从最终斜率推导的公式，测定结果会略微更准确（p<0.001）。如果用于计算51Cr-EDTA Cl，为测定99mTc-DTPA Cl推导的单样本公式往往会略微高估GFR。
