Impact of high temperatures on enzyme-linked immunoassay (ELISA) performance for leptin measurements in human milk stored under varied freeze/thaw conditions

Our aim is to provide researchers with information to make informed decisions regarding use of ELISAs that arrive in suboptimal conditions as well as potential effects on assay measurements. Due to unexpected shipping conditions from the manufacturer, leptin ELISA kits arrived at our university laboratory in a warm condition (76.3°F/24.6°C), well above the 2-8°C temperature conditions recommended by the manufacturer. Since no data was available on the effects of high temperature exposure during transportation on the performance of this commercial assay, we opportunistically assessed assay performance with human milk measurements due to the growing importance of leptin on lactation and breastfeeding investigations as well as the ever-present risk of in-transit high temperature exposure. We found that assay kit exposure to high temperature during shipping resulted in sample results that were significantly different from temperature-controlled kits despite similar standard curve performance.