Pregnancy: Unfortunately at this time, Signatera cannot be performed in patients who are pregnant, however, this is not a contraindication for Altera (yes Altera can be performed in pregnant patients). Donor bone marrow/stem cell transplants: No, neither Signatera nor Altera can be performed in patients with a history of donor bone marrow or stem cell transplant. Organ Transplant: If the donor organ received is impacted by cancer (i.e. the tumor tissue being sent for testing derived from the donated organ), neither Signatera nor Altera, can be performed. However, if the patient happened to have had a transplant BUT the donated organ is NOT involved in the cancer diagnosis, then we can perform Signatera and/or Altera.