When diagnostic tests are implemented in clinical studies there are multiple considerations beyond just the assay and the analyte that are not generally considered but are important. For example: Sample collection, preparation and transport
Standards need to be specified for pre-analysis that would specify the conditions needed even before the analysis are done.
Selection of tubes – The tubes that are used for collection can affect the analyte and need to be carefully considered
Timing of sample transit: How long does it take for the sample to arrive at the testing facility after collection from the patient
Storage: Storage of the samples during transit or even after the transit need to be clear and specified before it can be used.
There are other considerations for samples but this quickly illustrates that the sample journey should be considered in addition to assay parameters: such as limit of detection, thresholds for specificity and sensitivity, causes of interference and other assay specific parameters.
