Guardant Health is collecting real-world validation data for its multi-cancer detection blood test (Shield MCD), now nearly a year after launch as an opt-in add-on to its Shield colorectal screening assay. The company said the data collection is meant to refine the algorithm in an intended-use setting and potentially support a future regulatory submission. Shield MCD is offered as a laboratory-developed test with breakthrough device designation, while Shield itself is FDA-approved for colorectal cancer screening. Guardant said the assay detects nine additional cancers using DNA methylation on the same platform as Shield. In prior clinical validation, Guardant reported 98.5% specificity and 60% sensitivity across cancer types detected, and it is now using real-world data as a “pre-study” before formal prospective work, including participation in the National Cancer Institute’s Vanguard evaluation of MCED approaches.