Companion diagnostics analyze your DNA to determine if your genetics are a match for a given drug.
Current Companion Diagnostic tests are specialized kits, which run on expensive and complex technology platforms that are not feasible for clinical settings.
Consequently, all companion diagnostic testing is currently performed away from patient clinics at independent reference and specialty labs preventing patients and clinicians from quickly receiving valuable information
The current process of a doctor obtaining a tissue biopsy and shipping it to a central lab takes anywhere from 7-14 days to obtain a diagnostic result due to the number of samples that must be simultaneously batched and processed at the reference lab.
Even when a companion diagnostic is unequivocally required in drug labeling, not all doctors order testing for a variety of reasons, including lengthy turnaround times for results and difficulty getting a tumor sample.
— GenomeWeb - February 2016