Spike-and-recovery and linearity-of-dilution tests are crucial for validating and evaluating ELISA accuracy. Spike and recovery assesses if analyte detection varies due to differences in standard curve diluent and biological sample matrix. Linearity of dilution gauges how linearly a spike or natural sample's dose response behaves within the desired assay range. These methods are interconnected, allowing for simultaneous testing. The subsequent discussion explores each method separately.