The repetitive use of samples to measure multiple cytokines: the sequential ELISA.

The inexpensive and highly effective enzyme-linked immunosorbant assay (ELISA) is widely used for the quantification of biomarkers in a variety of biological samples. The applicability of the standard ELISA is difficult when experiments yield low volume samples. In such studies, the capacity of sample collection system does not meet the sample volume requirements to measure multiple different cytokines by the traditional ELISA protocol. In the modified methodology of the sequential ELISA, samples are re-used in multiple successive cycles, dramatically increasing the number of biomarkers which may be measured. Although the protocols presented to date were developed for quantification of cytokines in either blood plasma or cerebrospinal fluid, the sequential ELISA protocol has wide potential for further uses. When only limited quantities of samples are available for analysis, the sequential ELISA technique based on commercially available antibody pairs can be an attractive alternative to more advanced, costly multiplex methods. Additionally, any laboratory that currently runs traditional ELISAs has all the necessary equipment and reagents to perform the sequential ELISA.