Evaluation of the Stability of the Most Common Inflammatory Markers in Cows

Assessment of the stability of inflammatory parameters in bovine blood samples is important because it enables evaluation of the impact of preanalytical factors on biomarker preservation, standardization of sample processing and storage conditions, as well as reliable and consistent interpretation of results in diagnostic and research studies. The aim of the work was to evaluate the stability of the most common inflammatory markers in the blood of cows in early lactation. The influence of the serum–clot contacts duration and the storage of the separated serum in 24 cows, at 25 °C and 4 °C, in intervals of 0–24 h, was examined. Concentrations of interleukin 1 and 6 (IL-1, IL-6), tumor necrosis factor α (TNF-α), interferon γ (IFN-γ), haptoglobin (Hp), serum amyloid A (SAA) and extracellular heat shock protein 70 (eHsp70) were determined by ELISA method, stability was assessed by ANOVA analysis and maximum permissible instability method. Stability was determined over a range of 2–15 h for IL-1, 8–24 h for IL-6, 9–13 h for TNF-α, 10–20 h for IFN-γ, 20–24 h for Hp, 15–24 h for SAA, and 9–12 h for eHsp70. The stability was strongly dependent on temperature and sample type, with storage at 4 °C providing the highest stability in most cases, while differences between serum and serum–clot samples were analyte-specific and less consistent compared to the effect of temperature.