Is the sensitivity of the ELISA kit for the detection of cell supernatant VEGF different between domestic and imported?

The difference between the sensitivity of domestic and imported VEGF ELISA can not be judged only by the brand. The core depends on the applicability of the matrix declared by the antibody pairing, standard traceability, sample dilution, quantitative range and instructions. The cell supernatant often contains medium components, BSA, cytokines, and endogenous VEGF, and whether it can be detected at low concentrations depends on the lower limit of detection, quantitative range, and inter-well repeatability. It is recommended to keep the imported kit as a control, purchase domestic small specification candidate products, and use the same batch of supernatant for standard recovery, dilution linearity, repeatability, and inter-batch differences. If the sample concentration is close to the lower limit of detection, preference should be given to products with a low background and quantitative range covering low values, rather than just looking at the nominal sensitivity numbers.

The sample size of 80 supernatants is not large, but manual simple washing of the plate is easy to magnify the difference between the holes, especially the unevenness of the strip plate and the multiple addition of liquid. If there is no automatic plate washing machine, it is recommended to fix the number of plate washing, soaking time, plate beating force and water absorption direction, use removable strips to reduce edge effects, and set repeated hole monitoring consistency. Double antibody sandwich ELISA is optional on the kit type, and it is confirmed that it is suitable for cell culture supernatant or conditioned medium; if the interference of the medium is obvious, a sample dilution compatibility test can be performed first, or the sample can be diluted appropriately and then loaded. Color development and reading should also control the time to avoid inconsistencies in the background caused by residual wash plates in different strips.