It is generally advisable to analyze both commercial calibrators and primary standards together, when possible, to see if they agree. Any disagreement should be resolved prior to performing the recovery, interference, and comparison of methods experiments. In US laboratories, the CLIA regulations define which characteristics need to be validated for methods with difference classifications of complexity. Fewer studies are required with less complex methods. More extensive testing is necessary for methods developed by the laboratory or modified by the laboratory.
Sensitivity is determined by a detection limit experiment.
Reference intervals can be verified by testing samples from healthy people. It's actually the reportable range that must be validated. The objective in determining reportable range is to define the highest value that can be reported without diluting the sample. This is usually done by performing a linearity type of experiment, but there is no strict requirement that the method response has to be linear. However, the readout from instrument systems often is linear in the units that are reported.