Evaluation of the FI-Lab, a laboratory-based, automated frailty index for acute care: A multicohort study - Hugh Logan Ellis; Peter Hanlon; Liam Dunnell; Martin Whyte; Daniel H. J. Davis; Josephine Bates; Adeel Jafri; Diana Shamsutdinova; James T. Teo; Zina Ibrahim; Kenneth Rockwood (PLOS Medicine, 2026)