These are the last two phases of assay development before you can market your assay. One must verify the design inputs (product specifications) and validate that the biomarker is meeting the intended use of the customer.
Verification typically involves testing all of the design requirements that were characterized during the previous phases. It is generally not a good practice to enter this phase with an uncharacterized design input, like HAMA interference or endogenous protein levels. Verification is basically "checking the box" to say, yes, this is performed as we expected. Often poor characterization can lead to lots of issues and design rework in this phase. One of the most important studies and often challenging to execute is calibrator and reagent stabilities, which must be tested in their final form that is delievered to the customer. Both of these studies can be the gating item for product to market so it's important to get them started early!
Validation of the biomarker is likely one of the most expensive final tasks as you will need to conduct testing across a minimum of one clinical site. The site must be chosen well and should represent, if possible, a site where the intended use population is getting medical care. There are several pre-steps in setting up a clinical site:
Of course the Pivitol Study, where the biomarker is used to make some type of clinical predictive outcome, is the primary goal of the validation study. The "passing" criteria must be set ahead of time and must be a statistically based outcome. If, however, you are just making a test that already has regulatory approval, then a simple method correlation can be used to show biomarker agreement between two test methods.