A method for measuring multiple cytokines from small samples

Commercially available enzyme-linked immunosorbent assay (ELISA) kits are commonly used to assess levels of proinflammatory cytokines in biological samples. Most of these kits require sample volumes of at least 50 μl. Thus, in order to examine multiple cytokines, volumes greater than 100 μl must be collected. However, the volume of many biological samples, especially those collected from the central nervous system (i.e., microdialysates, push–pull perfusions, or cerebrospinal fluid samples), is much less than 100 μl. Therefore, we developed a method for analyzing multiple cytokines from a single, low-volume biological sample, which involves serially assaying the samples on multiple proinflammatory cytokine ELISA kits. In many cases, assaying for one cytokine does not interfere with subsequent assay for another cytokine in the same sample. Moreover, when interference is observed, the interfering factor can be identified and its effect minimized.