Questionable accuracy of four ELISA kits in serum Netrin-1 measurement

Abstract Objectives Altered serum Netrin-1 levels have been widely reported in cancer and other clinical diseases and they are often measured by commercial ELISA kits. However, we found the questionable results using these kits and therefore performed this simple study to evaluate their accuracy in detection of serum Netrin-1. Methods Four commonly used commercial kits were collected. The kit standards were serially diluted or spiked into serum samples. The cells with confirmed expression of Netrin-1 and their culture medium, as well as the Netrin-1 controls of each kit were used for the kits to detect. The cell lysate samples and the kit controls were also blotted on a nitrocellulose membrane for detection antibodies of each kit to probe. Results Detection of the Netrin-1 standards in serum by each kit were all affected. Only one kit was able to detect Netrin-1 in the cell lysate or medium. No ELISA kits could detect all Netrin-1 controls of the four kits. None of the detection antibodies correctly probed Netrin-1 in the dot blot. Conclusions The accuracy of these four Netrin-1 ELISA kits is under question. Reported serum Netrin-1 levels based on measurements by these kits need be carefully interpreted.