In agreeance with Scott’s comment about the extent of the validation required, I have experience with similar guidelines in my position. Firstly, a standard is set for the immunoassay instrument to meet of the concentration of known analyte it is able to detect in its optimal operating state. Multiple R&D instruments are repeatedly built and tested for accuracy to get a good representation of the range of values that are deemed acceptable. Then, through statistics, the acceptable guidelines are established for a ‘working’ instrument. As the instruments begin their production phase, patterns in the pass/ fail of each of the hundreds of analytes begin to appear. If a particular immunoassay testing analyte has a pattern of a high probability pass rate, then the number of replicate tests in the validation can be lower due to the observed higher pass rate. If the problem is deemed to be more common (observation made by R&D in initial testing) then the validation procedure will include many more replicated to ensure that all mistakes are caught when the instrument are being built in the commercial phase.