Broad Clinical Labs, in collaboration with Roche Sequencing Solutions and Boston Children’s Hospital, reported an ultra‑rapid whole‑genome sequencing workflow that produced variant calls in roughly four hours from genomic DNA. The team ran 15 human genomes on Roche’s early‑access Sequencing‑by‑Expansion (SBX) platform, achieving a mean turnaround of 4 hours 4 minutes and a fastest case under four hours. SBX is a novel sequencing chemistry that expands molecules to increase signal and throughput; the paper appears in the New England Journal of Medicine and was presented at ASHG. Broad described the result as a benchmark for same‑day clinical testing in critical care settings such as neonatal intensive care, while noting broader validation and practicality work remain before routine clinical deployment.