Influence of preanalytical and analytical factors on the quantification of six regulatory serum proteins

Background: We analyzed differences in protein concentrations in human blood serum depending on the tube material and the immunoassay platform used. Materials & methods: Blood samples from study participants were collected in glass and polypropylene tubes (n = 292). Serum concentrations of six proteins (BDNF, IGF-1, VEGF-A, TGF-& beta;1, MCP-1 and IL-18) were assessed by using ELISAs (all biomarkers), as well as a novel fully automated immunoassay platform (all but IGF-1, n = 211). Bland-Altman analyses were conducted to investigate intrasample variability of protein concentrations. Results: Tube comparison resulted in mean biases of between -0.45 and -70.64%. Platform comparison revealed mean biases of between 21.04 and -128.10%. Conclusion: Protein concentrations can vary significantly depending on the types of tube and immunoassay used, with protein-specific differences. This study investigated the impact of blood tube materials and measuring platforms on protein concentrations in blood samples. We collected blood serum from up to 292 study participants using glass and polypropylene tubes. The concentrations of six proteins were analyzed using a common laboratory technique called ELISA, as well as an automated platform, Ella & TRADE;.The choice of tube material had small effects on two proteins (IGF-1 and IL-18), with differences of less than 1%. However, the concentrations of four other proteins (VEGF-A, MCP-1, TGF-& beta;1 and BDNF) varied significantly more depending on the tube material used, with differences ranging from -32.17 to -70.64%.With the two testing methods, two proteins (VEGF-A and TGF-& beta;1) showed only small differences, with variations of -7.68 and 11.74%, respectively. For the other four proteins, the differences were larger, from 21.04 to -128.10%.The study demonstrates the importance of having consistent, standardized methods for measuring protein levels in blood samples. The tubes and testing methods used can both change the results significantly, depending on the specific protein being measured. To make sure the measurements are accurate, we suggest creating specific guidelines for each testing method and protein. By following these guidelines, scientists can ensure that the measurements of protein levels in liquid biopsy samples are dependable and consistent. Differing procedures affect protein measurements in human blood. We analyzed differences in six proteins between tube materials & assay platforms. Results show variations, highlighting the need for standardization.