Vassalle Cristina, Masini Silvano, Carpeggiani Clara, L'Abbate Antonio, Boni Claudio, Zucchelli Gian Carlo
CNR Institute of Clinical Physiology, Pisa, Italy.
Clin Chem Lab Med. 2004 Jan;42(1):84-9. doi: 10.1515/CCLM.2004.016.
Several methods to assess the total antioxidant capacity (TAC) are available. However, the final value of measured TAC in the sample depends on the procedure used in every specific assay. This makes crucial the comparison of different analytical methods. The aim of our study was to evaluate analytical characteristics and laboratory reliability of two different assays: the ferric-reducing ability (FRAP) assay and a new spectrophotometric test (OXY-adsorbent test, Diacron, Italy). Unselected outpatients referred to the Institute of Clinical Physiology were studied (n = 187, 58 females, 129 males, mean age: 65 +/- 13 years). All blood samples were maintained on ice, centrifuged within 15 minutes after blood collection and then stored at -80 degrees C until performance of assay procedures. OXY assay: The lower limit of sensitivity was 6 micromol HClO/ml. The assay was found to be linear up to 440 micromol HClO/ml (r = -0.99, p < 0.001). Absorbance was linear over a wide concentration range with solutions containing uric acid in purified form (0-1000 micromol/l, r = -0.996, p < 0.001), serum (r = -0.99, p < 0.01) or plasma serially diluted (r = -0.99, p < 0.01). Mean value in plasma samples accounted for 366.2 +/- 7.2 micromol HClO/ml. Mean OXY value in females (353.4 +/- 13.2 micromol HClO/ml) was not different from that detected in males (372 +/- 8.6 micromol HClO/ml). A significant difference was observed between subjects without and with hypertension in serum OXY levels (344.8 +/- 9.9 and 383.2 +/- 10 micromol HClO/ml, p < 0.01, respectively). FRAP assay: The lower limit of sensitivity was 15 micromol/l. Linearity was observed up to 1000 micromol/l (r = 0.998, p < 0.001). Absorbance was linear over a wide concentration range with solutions containing uric acid in purified form (0-1000 micromol/l, r = 0.997, p < 0.001), serum (r = 0.99, p < 0.01) or plasma serially diluted (r = 0.99, p < 0.01). FRAP mean value in plasma samples, evaluated in 102 patients, accounted for 514.1 +/- 19.1 micromol/l. Mean FRAP in females (469 +/- 22.5 micromol/l) was not different from that detected in males (535 +/- 25.6 micromol/l). FRAP vs. OXY: A significant direct relationship was observed when comparing FRAP with OXY levels in the whole population (r = 0.22, p < 0.05). Neither of the methods are expensive and they are speedy and simple to perform. Values are reproducible and linearly correlated to the concentration of antioxidants present in the samples. For this reason, these methods may be considered practicable indicators of total antioxidant capacity, for routinely potential use in every laboratory and useful in all the studies concerning the evaluation of oxidative stress.
有几种方法可用于评估总抗氧化能力（TAC）。然而，样品中测得的TAC最终值取决于每个特定检测中所使用的程序。这使得不同分析方法的比较至关重要。我们研究的目的是评估两种不同检测方法的分析特性和实验室可靠性：铁还原能力（FRAP）检测和一种新的分光光度法检测（OXY吸附剂检测，Diacron公司，意大利）。对转至临床生理研究所的未挑选门诊患者进行了研究（n = 187，女性58例，男性129例，平均年龄：65±13岁）。所有血样均保存在冰上，采血后15分钟内离心，然后储存在-80℃直至进行检测程序。OXY检测：灵敏度下限为6微摩尔HClO/ml。该检测在高达440微摩尔HClO/ml时呈线性（r = -0.99，p < 0.001）。在含有纯化形式尿酸的溶液（0 - 1000微摩尔/升，r = -0.996，p < 0.001）、血清（r = -0.99，p < 0.01）或系列稀释的血浆（r = -0.99，p < 0.01）中，吸光度在很宽的浓度范围内呈线性。血浆样品中的平均值为366.2±7.2微摩尔HClO/ml。女性的平均OXY值（353.4±13.2微摩尔HClO/ml）与男性检测值（372±8.6微摩尔HClO/ml）无差异。在无高血压和有高血压的受试者之间，血清OXY水平存在显著差异（分别为344.8±9.9和383.2±10微摩尔HClO/ml, p < 0.01）。FRAP检测：灵敏度下限为15微摩尔/升。在高达1000微摩尔/升时观察到线性（r = 0.998，p < 0.001）。在含有纯化形式尿酸的溶液（0 - 1000微摩尔/升，r = 0.997，p < 0.001）、血清（r = 0.99，p < 0.01）或系列稀释的血浆（r = 0.99，p < 0.01）中，吸光度在很宽的浓度范围内呈线性。在102例患者中评估的血浆样品中FRAP平均值为514.1±19.1微摩尔/升。女性的平均FRAP值（469±22.5微摩尔/升）与男性检测值（535±25.6微摩尔/升）无差异。FRAP与OXY比较：在比较整个人群中的FRAP和OXY水平时观察到显著的直接关系（r = 0.22，p < 0.05）。这两种方法都不贵，且操作快速简便。结果具有可重复性，并且与样品中存在的抗氧化剂浓度呈线性相关。因此，这些方法可被视为总抗氧化能力的实用指标，可在每个实验室常规潜在使用，并且在所有关于氧化应激评估的研究中都很有用。
