“For diagnosis of tumor, you will need a conventional tissue biopsy. If your liquid biopsy is negative for certain mutations, you may need to have follow-up testing done on a conventional biopsy specimen. A liquid biopsy may miss details available from a conventional tissue biopsy and can't determine where in one's body a mutation has arisen.
In some situations, a liquid biopsy alone can provide sufficient information for making treatment decisions. It may be sufficient if, for example, the primary test is positive for a mutation or if a T790M mutation is detected and a tissue biopsy cannot be obtained. While liquid biopsies are promising and powerful tools, they complement but do not necessarily replace tissue biopsies for the foreseeable future."
