What should you know about a Signatera liquid biopsy?

A blood sample is analysed for circulating tumour DNA that matches a tumour profile. Depending on the clinical setting, the result may contribute to discussions about residual disease, recurrence monitoring, or response to treatment. It is an additional source of information, not a replacement for examination, scans, or tissue pathology.

A result can be difficult to interpret if there is little tumour DNA in the blood or if the available tumour sample is not suitable for comparison. Your oncologist considers the result alongside the cancer type, treatment history, symptoms, and other tests.

Ask whether the laboratory needs a previous tumour sample, a pathology report, or specific information from your oncology records. Confirm where the blood will be taken and how results will be communicated. Most people can prepare for a blood draw in their usual way unless the clinic gives different instructions.

Tell the phlebotomist if you have previously felt faint with blood tests. Afterward, keep pressure on the puncture site as advised and mention persistent bleeding, increasing swelling, or significant pain.

Seek advice for bleeding that does not settle, spreading redness, increasing pain, or swelling at the needle site. A liquid-biopsy result itself is not an emergency; contact your oncology team if a result causes worry or you need help understanding what it means for your treatment plan.

Ask what decision this test may inform, whether it is being used for monitoring or another purpose, how a positive or negative result would be interpreted, what limitations apply to your cancer, and whether a scan or tissue biopsy remains necessary.