Investigation of the use of impermeable fluid barriers between pelleted and supernatant enzyme activity in a pseudohomogeneous enzyme immunoassay.

We have investigated the feasibility of performing an automated pseudohomogeneous enzyme immunoassay in which a separation step is not apparent to the user. This was achieved using a layer of silicone fluid, which is immiscible with aqueous solutions, as a physical barrier between the pelleted and supernatant enzyme. Initially we produced a manual assay based on the Serozyme T4 assay to demonstrate the feasibility of the approach. This assay showed good precision, parallelism and correlated with 'in house' results on patients' samples. Production of a fully automated assay was made difficult by the design of available equipment but none the less we demonstrated the feasibility of the automated approach by producing a standard curve for T4.