When Minutes Matter

Sepsis is one of the most time-critical diagnoses a hospital can make. In the most severe cases, it’s estimated that patients’ likelihood of survival decreases by 7.6 percent each hour that passes without effective treatment (1). But with common symptoms like fever and pain, it can be difficult to conclusively identify sepsis in a timely manner.

The lab-on-a-chip system that uses a patient’s immune response to diagnose sepsis.Credit: Janet Sinn-Hanlon

Fortunately, science is on the case. Two groups of researchers have recently published tests that promise rapid, reliable diagnosis of sepsis: one, a new PCR-based method, and two, a portable lab-on-a-chip device. The first, a TaqMan-based multiplex real-time PCR detection system, probes conserved regions of the 16S rDNA gene in 10 common bacterial pathogens (2). It not only detects the organisms causing sepsis, but also positively identifies them in a matter of hours, ensuring that patients can receive appropriate antibiotic treatment as soon as possible – and freeing doctors from the need to wait a day or more for blood cultures to provide the same information.

The second test takes a unique approach – instead of looking for the cause of infection, it detects the patient’s immune response (3). How? The device takes a complete white blood cell count, a neutrophil count, and measures levels of the CD64 neutrophil cell surface marker. As the immune response increases, so do these numbers, giving doctors a rapid heads-up that the patient’s condition is deteriorating. In some cases, the immune response can spot sepsis even before the causative pathogen is detectable in the blood. “We think we need both approaches,” said Rashid Bashir, senior author on the latter study. “Detect the pathogen, but also monitor the immune response. (4)”

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