Great Ormond Street Hospital has introduced a same-day genetic sequencing service for children in intensive care, with a study finding that results influenced treatment or diagnosis in 29 per cent of samples analysed.
The respiratory metagenomics service searches a sample’s genetic material for bacteria, viruses and fungi at once. Conventional tests tend to look for a limited set of organisms selected in advance. The broader approach can therefore reveal infections that were not initially suspected, as well as organisms that routine testing did not detect.
The paediatric service was run in GOSH’s general and cardiac intensive care units, including its extracorporeal membrane oxygenation service, during the 2024–25 winter. The study analysed 177 respiratory samples from 122 critically ill children. Samples received by 9am could receive preliminary results later the same day; the final report followed the next morning.
What the study found
In the study’s analysis of 174 samples with clinical-impact data, results were judged to have influenced patient management in 51 cases. Antimicrobial prescribing was affected in 46 samples: the findings led clinicians to stop or start antibiotics, change treatment, or retain an existing choice with greater confidence. Eight samples had an impact on diagnosis, while four had potential infection-control or public-health implications.
Testing also identified 50 organisms in 42 samples that had not been found by the routine diagnostic workflow. Those detections were subsequently confirmed using separate tests. The researchers reported high specificity across bacteria, viruses and fungi, but the test was not error-free: comparison with routine results identified occasional false negatives and one possible false positive.
Metagenomics does not replace clinical judgement or every conventional test. In several cases, routine testing detected viruses that the sequencing analysis missed, and those results informed infection-control decisions. The study’s authors said the approaches can provide complementary evidence. The sequencing process can also identify genetic markers for only a limited range of antimicrobial resistance; it cannot routinely predict whether every detected bacterium will respond to a particular medicine.
From service to wider use
The study was a prospective observational evaluation at one specialist hospital over a single winter season. Clinicians selected samples as part of standard care, and the effect on management was assessed retrospectively. The findings show how the service operated in that setting, but do not establish that it improves survival or that the results will be the same in every hospital. The researchers called for further refinement and studies across multiple centres, including assessment of clinical impact and cost-effectiveness.
The work builds on a rapid respiratory testing pathway first developed at Guy’s and St Thomas’ and adapted for children at GOSH. The national NHS Respiratory Metagenomics Network is working to extend rapid testing across hospitals. The GOSH team described the paediatric implementation as the first same-day pan-microbial metagenomics service of its kind for children in intensive care.
For families, the potential value is a broader search when a critically ill child’s infection is difficult to identify. One child treated at GOSH had pneumonia linked to a bacterium resistant to the antibiotic initially prescribed; sequencing helped identify the organism and its resistance. That individual case illustrates how the test may inform care, but it does not by itself establish how often the service changes outcomes.
With the study’s limits acknowledged, the results point to a practical role for rapid sequencing alongside established diagnostic methods: giving intensive-care teams additional evidence while they make time-sensitive decisions about infection and treatment.
