Same-day metagenomic test finds hidden infections in critically ill children at Great Ormond Street

Great Ormond Street Hospital (GOSH) has implemented a pioneering same-day respiratory metagenomics testing service for children in intensive care. Published in The Lancet Microbe on 16 October 2026, the study marks the first such same-day pan-microbial service for children.

The team analysed 177 respiratory samples from 122 critically ill children during the 2024-25 winter season. Metagenomics sequences all genetic material in a sample, detecting bacteria, viruses and fungi without needing to guess the pathogen in advance. It identified around nine in ten bacteria and viruses and all fungi, plus 50 organisms missed by routine testing. Results altered clinical management in 29% of samples and influenced antimicrobial prescribing in 26% of cases.

One patient, ten-year-old Willow, had severe pneumonia and a drug-resistant bacterial infection that the test identified, allowing doctors to switch antibiotics. Her family credits the test with helping save her life.

The service builds on earlier work at Guy’s and St Thomas’ NHS Foundation Trust and is part of the NHS Respiratory Metagenomics Network funded by the Department for Science, Innovation and Technology. It is being gradually rolled out to around 30 intensive care units across the UK that treat adults and children.

Background

Traditional diagnostics rely on culturing bacteria (slow, Victorian-era methods) or targeted PCR that requires clinicians to specify what they are looking for. Metagenomics is untargeted: it sequences everything present and can flag novel or unexpected pathogens. Earlier GOSH work established accredited metagenomics for harder-to-diagnose cases; the new implementation brings same-day turnaround specifically for respiratory samples in paediatric ICU.

What changed

Same-day results mean clinicians can start, stop or change antibiotics within hours rather than days. The study showed high sensitivity and specificity, with clinical impact in nearly one-third of cases. This supports better antimicrobial stewardship—avoiding unnecessary broad-spectrum antibiotics while catching resistant organisms faster.

Competing viewpoints

Supporters highlight the potential to reduce mortality in critically ill children, detect emerging threats earlier, and improve antibiotic use. Critics note the high cost (NHS price around £1,346 per test in related services), the need for specialised lab infrastructure, and the risk of over-interpreting incidental findings. Access remains limited to specialist centres for now; wider rollout will test scalability and cost-effectiveness. Some infectious-disease reviews caution that clinical impact data are still emerging and that metagenomics should complement, not replace, standard tests.

What to watch next

Rollout to the planned 30 ICUs, real-world outcome data on mortality and length of stay, cost-effectiveness studies, and whether the technology expands to other sample types or lower-acuity settings. Parents of children with complex or recurrent infections may see faster answers in specialist centres. Broader antimicrobial-resistance surveillance benefits are also possible if the network shares findings nationally.

Sources: GOSH news release, BBC News coverage of the Lancet Microbe paper, and related NHS network announcements (16 October 2026).