Haystack Oncology, part of Quest Diagnostics, launched Haystack MRD®, a tumor‑informed circulating tumor DNA (ctDNA) workflow designed to detect minimal residual disease (MRD) with high sensitivity. The personalized assay uses whole‑exome sequencing of tumor tissue and white blood cells to create a bespoke panel that enriches up to 50 patient‑specific variants for plasma surveillance. Clinical adopters at cancer centers are integrating the test with imaging and standard clinical assessments to refine postoperative monitoring and treatment adaptation. Quest and Haystack emphasize integrated error‑correction and bespoke panels to overcome low‑frequency ctDNA noise in plasma. The approach targets surgical oncology and adjuvant decision contexts where early MRD detection can change systemic therapy choices. For readers: tumor‑informed MRD assays compare tumor genotype to circulating DNA to minimize false positives from clonal hematopoiesis or technical artifacts.