Paddington Cat Hospital, Paddington, NSW, Australia.
SYNLAB-VPG/Exeter, Exeter, UK.
Vet Clin Pathol. 2021 Mar;50(1):57-61. doi: 10.1111/vcp.12951. Epub 2021 Feb 1.
Symmetric dimethylarginine (SDMA) reflects the glomerular filtration rate (GFR) in people, dogs, and cats. Initial assays used a liquid chromatography-mass spectroscopy (LC) technique. A veterinary immunoassay has been developed for use in commercial laboratories and point-of-care (POC) laboratory equipment. There have been no independent assessments of these assays, and analytical performance goals for SDMA testing have not been defined.
This study sought to establish analytical performance goals for SDMA in cats from (a) biological variation (BV) data and (b) expert opinion.
Analytical performance goals were determined from a prior BV study of SDMA in cats and a survey of veterinary internists who have used SDMA in practice.
Biological variation-based performance goals included an imprecision of ±10% (immunoassay and LC), bias of ±8% (immunoassay and LC), and total error of ±24% (immunoassay and LC). Expert opinion performance goals were ±0.10 μmol/L (±2 μg/dL), or ±0.15 μmol/L (±3 μg/dL), varying with starting SDMA concentrations.
This study recommends analytical performance goals for SDMA based on BV and expert opinion. Wide dispersion of SDMA results using currently available assays implies that clinicians risk attaching medical significance to small SDMA changes that actually reflect analytical variability.
对称二甲基精氨酸（SDMA）反映了人类、犬类和猫类的肾小球滤过率（GFR）。最初的检测方法采用液相色谱-质谱（LC）技术。现已开发出一种用于商业实验室和即时检测（POC）实验室设备的兽医免疫测定法。这些检测方法尚未经过独立评估，也没有定义 SDMA 检测的分析性能目标。
本研究旨在从（a）生物学变异（BV）数据和（b）专家意见两个方面为猫的 SDMA 确定分析性能目标。
分析性能目标是从先前对猫的 SDMA 的 BV 研究和对在实践中使用 SDMA 的兽医实习医生的调查中确定的。
基于生物学变异的性能目标包括 ±10%（免疫测定法和 LC）的不精密度、±8%（免疫测定法和 LC）的偏倚和 ±24%（免疫测定法和 LC）的总误差。专家意见的性能目标为 ±0.10 μmol/L（±2 μg/dL）或 ±0.15 μmol/L（±3 μg/dL），具体取决于起始 SDMA 浓度。
本研究建议基于 BV 和专家意见为 SDMA 确定分析性能目标。目前可用的检测方法得到的 SDMA 结果分布广泛，这意味着临床医生可能会将 SDMA 的微小变化与实际反映分析变异性的医学意义联系起来。
