A novel method for automating zone measurement of SRD assays

Single radial immunodiffusion (SRD) is a simple yet powerful technique that is routinely used in many clinical laboratories for a wide variety of analyses. Despite its simplicity, the technique as currently practiced suffers from a major drawback due to the fact that in general, the measurement of the reaction zones generated by the assay is performed manually. This is a task that is time-consuming and error-prone. To overcome these problems, a novel method of automating inhibition zone measurement has been developed. The new system has been extensively tested and compared with the standard, manual method. We report here the performance of the new method in the assay of the potency of influenza vaccines.