Paraoxonase-1 (PON-1) activity is a new inflammatory and oxidative marker. Technical effects and biological factors could affect the accuracy of PON-1 activity measurement. We investigated the effects of storage at different temperatures, repeated freeze–thaw cycles, interferences from hemolytic, lipemic, and icteric samples, and seasonal effects on PON-1 activity in horses. We evaluated 2 substrates with an automated spectrophotometer. Ten equine serum samples were stored under different conditions. Although storage at room (21°C) or refrigeration (4°C) temperature induced a statistically significant decrease (p < 0.05) in PON-1 activity, this is not diagnostically relevant. PON-1 activity in frozen samples (−20°C) was stable for short-term storage; diagnostically significant (p < 0.01) fluctuations were observed after 1 mo. Four repeated freeze–thaw cycles were assessed, and all cycles affected PON-1 activity (p < 0.01); however, this was diagnostically significant only after the 4th cycle. Hemolysis induced an overestimation of PON-1 activity; lipemia and hyperbilirubinemia did not change PON-1 activity. Thirty-four horses were sampled monthly for 1 y, and PON-1 activity was higher in autumn (p < 0.05) and winter (p < 0.05) than in spring and summer.

对氧磷酶-1 (PON-1) 活性是一种新的炎症和氧化标志物。技术效应和生物因素会影响 PON-1 活性测量的准确性。我们研究了不同温度下储存的影响、反复冻融循环、溶血、脂血和黄疸样品的干扰，以及季节性对马 PON-1 活性的影响。我们使用自动分光光度计评估了 2 个基板。十份马血清样品在不同条件下储存。尽管在室温 (21°C) 或冷藏 (4°C) 温度下储存会导致PON-1 活性在统计学上显着降低 ( p < 0.05)，但这与诊断无关。PON-1 在冷冻样品 (-20°C) 中的活性对于短期储存是稳定的；具有诊断意义（p< 0.01) 1 个月后观察到波动。评估了四个重复的冻融循环，所有循环都会影响 PON-1 的活性（p < 0.01）；然而，这仅在第 4 个周期后才具有诊断意义。溶血导致对 PON-1 活性的高估；脂血和高胆红素血症不会改变 PON-1 的活性。34 匹马每月采样 1 年，PON-1 活性在秋季 ( p < 0.05) 和冬季 ( p < 0.05) 高于春季和夏季。