A new method for determining plasma water content: application in pseudohyponatremia.
A new method for determining plasma water content: application in pseudohyponatremia.
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测定血浆水含量的新方法：在假性低钠血症中的应用。
DOI：
10.1152/ajprenal.00493.2006
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Kurtz,Ira
中科院分区：
文献类型：
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作者：
Nguyen,MinhtriK;Ornekian,Vahram;Butch,AnthonyW;Kurtz,Ira
假性低钠血症是一种临床病症，其特征是血浆中蛋白质或脂质含量增加，从而导致血浆钠浓度（[Na+]p）人为降低。由于大多数实验室测量[Na+]pin的自动化方法涉及使用间接离子选择性电极（I-ISE），因此该方法无法校正升高的蛋白质或脂质浓度。在I-ISE中，在获得实际测量值之前稀释血浆样品，并基于血浆通常由93%血浆水组成的假设测定[Na+] p。因此，在临床条件下，当血浆含水量（PWC）<93%时，I-ISE测定的[Na+]pas将人为降低。相比之下，当使用直接伊势（D-ISE）测量[Na+] p时，血浆未稀释。该方法直接测量血浆水中的Na+活性，因此不受水占据的血浆比例的影响。在这项研究中，我们报告了一种新的定量方法来确定PWC利用I-ISE和D-ISE。为了验证这种新方法的实验，我们改变PWC在体外溶解不同量的无盐白蛋白在人血浆中。然后，我们测量PWC重量法在每个样品中，并比较重量测定PWC与ISE确定的PWC。我们的研究结果表明，PWC可以准确地确定的基础上测量的[Na+]PAS的差异I-ISE和D-ISE，这种新的定量方法可以是一个有用的辅助分析的dysnatrexine。
Pseudohyponatremia is a clinical condition characterized by an increased fraction of protein or lipid in plasma, thereby resulting in an artificially low plasma sodium concentration ([Na+]p). Since the automated method of measuring [Na+]pin most laboratories involves the use of an indirect ion-selective electrode (I-ISE), this method does not correct for elevated protein or lipid concentrations. In I-ISE, the plasma sample is diluted before the actual measurement is obtained, and the [Na+]pis determined based on the assumption that plasma is normally composed of 93% plasma water. Therefore, the [Na+]pas determined by I-ISE will be artificially low in clinical conditions when the plasma water content (PWC) is <93%. In contrast, the plasma is not diluted when the [Na+]pis measured using direct ISE (D-ISE). This method directly measures Na+activity in plasma water and is therefore unaffected by the proportion of plasma occupied by water. In this study, we report a novel quantitative method for determining the PWC utilizing I-ISE and D-ISE. To validate this new method experimentally, we altered the PWC in vitro by dissolving varying amount of salt-free albumin in human plasma. We then measured PWC gravimetrically in each sample and compared the gravimetrically determined PWC with the ISE-determined PWC. Our findings indicate that the PWC can be accurately determined based on differences in the [Na+]pas measured by I-ISE and D-ISE and that this new quantitative method can be a useful adjunct in the analysis of the dysnatremias.