Optimizers are a class of advantageous and multifunctional solutions for immunoassays. They are outstanding compared to other diluents and buffers. LowCross- Buffer® is the first solution that combines several functionalities of diluents in one product and is not only an assay diluent. Additionally it can reduce HAMA-interference and furthermore helps to avoid matrix effects. LowCross® HRP-Stab is another product with several functionalities. This product enables convenient one step incubation assays without negatively affecting the reliability of the results. This is due to both the optimizing and stabilizing properties of the solution. The casein based surface blocker “The Blocking Solution” is also part of the class of optimizers. The Blocking Solution shows outstanding blocking characteristics combined with a reduced background and a high sensitivity of the immunoassay.