Analysis of gene activity in a blood sample can help determine if a fever is caused by bacterial infection, a virus or an inflammatory disease
By Grace Wade
18 August 2023
Many childhood fevers are due to undiagnosed illnesses, but a blood test can identify potential causes
Shutterstock/Aleksandra Suzi
A blood test can determine whether a fever is caused by bacteria, viruses or an inflammatory disease using changes in gene activity.
About three-quarters of children hospitalised for fever don’t receive a diagnosis. Current diagnostic tools, which look for pathogens, are slow and sometimes unreliable, says Myrsini Kaforou at Imperial College London. Genetic tests are a promising alternative as certain genes switch on or off in response to disease.
Kaforou and her colleagues gene expression in blood samples from 1212 children who were between a few weeks to 18 years old. All had been diagnosed with one of 18 infectious or inflammatory diseases that cause fever.
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The researchers used a machine learning model to analyse this data, and identified 161 genes that correlate with diseases across six categories: bacterial infections, viral infections, inflammatory diseases, malaria, tuberculosis or Kawasaki disease. The researchers validated the model in a separate group of 411 children with fever, and assessed it using a statistical measure that estimates accuracy on a scale of 0 to 1. Across the disease categories, the team found that the model had a score of 0.89 to 1 – generally, a score of 0.8 or higher indicates excellent accuracy.
The finding could speed up diagnoses, ensure appropriate treatment and reduce unnecessary antibiotic use, which contributes to antibiotic resistance, says Kaforou.