15-F_2T-isoprostanes are byproducts of lipid peroxidation and were determined to be the best marker of oxidative injury in a rodent model of oxidative stress. A previous study compared methods for measurement of urinary F₂-isoprostanes (gas chromatography and negative ion chemical ionization–mass spectrometry, GC-NICI-MS; and ELISA) and found poor agreement in dogs, horses, and cows. Surprisingly, fair agreement between these methods was identified in a small population of cats. We evaluated the agreement between GC-NICI-MS and ELISA of urinary F₂-isoprostanes in the urine of 50 mature cats ranging from healthy to systemically ill. All urine samples had detectable levels of F₂-isoprostanes by both methods. Significant proportional bias and poor agreement were identified between the 2 methods (ρ = 0.364, p = 0.009) for all cats, and in subgroup analysis based on health status. The concentration of urinary F₂-isoprostanes was significantly lower in systemically ill cats compared to healthy cats when measured by ELISA (p = 0.002) but not by GC-NICI-MS (p = 0.068). Our results indicate that GC-NICI-MS and ELISA have poor agreement when measuring urinary F₂-isoprostanes in cats.

15-F _2T -isoprostanes是脂质过氧化反应的副产物和被确定为氧化损伤的最佳标志物在氧化应激的啮齿动物模型。先前的研究比较了尿中F _2-异前列腺素的测量方法（气相色谱法和负离子化学电离质谱法，GC-NICI-MS和ELISA），发现狗，马和牛的一致性差。出乎意料的是，在少数猫中发现了这些方法之间的合理协议。我们评估了从健康到系统性疾病的50只成熟猫的尿液中尿中F _2-异前列腺素的GC-NICI-MS和ELISA的一致性。所有尿液样本均具有可检测的F ₂水平-异前列腺素通过两种方法。在所有猫的两种方法之间以及根据健康状况进行的亚组分析中，均发现了显着的比例偏差和较差的一致性（ρ= 0.364，p = 0.009）。当通过ELISA（p = 0.002）而非GC-NICI-MS（p = 0.068）进行测量时，系统性疾病猫的尿中F _2-异前列腺素的浓度显着低于健康猫。我们的结果表明，在猫中测量尿中F _2-异前列腺素时，GC-NICI-MS和ELISA的一致性较差。