Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
Clin Biochem. 2013 Aug;46(12):1079-1083. doi: 10.1016/j.clinbiochem.2013.05.046. Epub 2013 May 23.
Soluble serum Klotho is a new biomarker linked to chronic kidney disease, cardiovascular disease and diabetes. This study describes the evaluation and comparison of two different immunoassays and establishment of assay specific reference intervals in adults.
Serum Klotho concentrations were determined in 120 healthy adults aged 19-66 years. Blood samples were collected, and stored sera were assayed for Klotho according to age and gender. In addition several other clinical and laboratory characteristics were determined in the cohort and compared to the levels of serum Klotho.
Serum Klotho levels were significantly higher in time-resolved fluorescence immunoassay (TRF) compared to an ELISA (IBL) and no correlation was found between the assays. No signal was obtained in either assay when the standard curve was switched between the two different immunoassays. The median serum Klotho concentration using TRF was 61 ng/mL (2.5-97.5% reference limits; 11-181 ng/mL) for males and 99 ng/mL (2.5-97.5% reference limits; 19-316 ng/mL) for females while the ELISA gave a mean value of 472 pg/mL (2.5-97.5% reference limits; 204-741 pg/mL) with no difference between genders. Concentrations of serum Klotho were independently associated with estimated glomerular filtration rate (eGFR) and body weight using TRF whereas serum Klotho concentrations were associated with age using the ELISA.
Comparison of two different immunoassays for serum Klotho indicate, that the protein exists in human beings in different forms which may function as independent factors and whose role and potential value as biomarkers needs to be evaluated separately. Reference intervals specific for the different forms recognized by the different assays were calculated in this study.
可溶性血清 Klotho 是一种与慢性肾脏病、心血管疾病和糖尿病相关的新型生物标志物。本研究描述了两种不同免疫测定法的评估和比较，并建立了成人专用的测定法参考区间。
检测了 120 名年龄在 19-66 岁之间的健康成年人的血清 Klotho 浓度。采集血样，根据年龄和性别检测储存血清中的 Klotho。此外，在队列中还确定了其他几个临床和实验室特征，并与血清 Klotho 水平进行了比较。
与 ELISA（IBL）相比，时间分辨荧光免疫测定法（TRF）中的血清 Klotho 水平显著升高，并且两种测定法之间没有相关性。当标准曲线在两种不同的免疫测定法之间切换时，两种测定法均未获得信号。使用 TRF 的中位数血清 Klotho 浓度为男性 61ng/mL（2.5-97.5%参考范围；11-181ng/mL），女性 99ng/mL（2.5-97.5%参考范围；19-316ng/mL），而 ELISA 给出的平均值为 472pg/mL（2.5-97.5%参考范围；204-741pg/mL），性别之间无差异。使用 TRF，血清 Klotho 浓度与估计肾小球滤过率（eGFR）和体重独立相关，而使用 ELISA，血清 Klotho 浓度与年龄相关。
两种不同的免疫测定法检测血清 Klotho 表明，该蛋白在人类中以不同的形式存在，可能作为独立因素发挥作用，其作为生物标志物的作用和潜在价值需要分别评估。本研究计算了不同测定法识别的不同形式的专用参考区间。
