Scientists say a new test for sepsis could cut diagnosis times from days to minutes.
Detecting the deadly illness is difficult because the symptoms are nondescript.
Current tests can take as long as 48 hours - problematic with an illness where every second counts.
Peter Ghazal, from Cardiff University's Project Sepsis, said early detection "dramatically improves" chances of survival.
"We're very excited. We think we can actually move this at least within five years, but hopefully before then, to actually being used in a clinical setting," he said.
It is estimated five million people die every year from the illness worldwide, which occurs when the body responds to an infection by injuring its own tissues and organs.
In Wales there are about 2,900 deaths annually.
Nicola Madoc-Jones' daughter Edie developed sepsis after being born prematurely at 23 weeks.
"They suspected she had sepsis so what they do is they take blood cultures, but unfortunately the results of the blood cultures take up to 48 hours," she said.
"And we don't have those hours to spare."
Two-and-a-half years later, Edie is a strong toddler but between 30 and 40% of premature babies suffering from sepsis will not survive.
The researchers have been trying to pick up signals in the blood from the "chatter of the immune system" to see if a patient is going to become sick.
This is done by conducting "millions" of experiments on small volumes of blood.
Researchers can then decipher signals from the chatter that indicate a patient is infected.
"This is a chatter that occurs very early on, so days before the current tests actually give you any signal," Prof Ghazal said.
"This is something that can be used as a very early warning to pick up in terms of a clinical diagnosis for sepsis."
"The test that we're looking at could be done within minutes to hours from first suspecting a patient might be septic," he said.
"If you don't detect sepsis in a patient, you can lose a life within hours, so the early recognition and the administration of antibiotics dramatically improves outcome in terms of survival."