Rapid test finds signs of sepsis in single drop of blood

Researchers have developed a new portable device that can quickly find markers of deadly, unpredictable sepsis infection from a single drop of blood.

In a clinical study, results from the rapid test correlated well with the results from the traditional tests, according to the findings published in the journal Nature Communications.

This can help doctors identify sepsis at its onset, monitor infected patients and could even point to a prognosis, said research team leader Rashid Bashir, Professor at the University of Illinois at Urbana-Champaign, US. 

Sepsis is triggered by an infection in the body. The body's immune system releases chemicals that fight the infection, but also cause widespread inflammation that can rapidly lead to organ failure and death.

"Sepsis is one of the most serious, life-threatening problems in the ICU. It can become deadly quickly, so a bedside test that can monitor patient's inflammatory status in real time would help us treat it sooner with better accuracy," said Karen White, an intensive care physician at Carle Foundation Hospital in Urbana, Illinois.

Sepsis is routinely detected by monitoring patients' vital signs - blood pressure, oxygen levels, temperature and others. 

If a patient shows signs of being septic, the doctors try to identify the source of the infection with blood cultures and other tests that can take days -- time the patient may not have.

The new device takes a different approach.

"We are looking at the immune response, rather than focusing on identifying the source of the infection," Bashir said. 

The small, lab-on-a-chip device counts white blood cells in total as well as specific white blood cells called neutrophils, and measures a protein marker called CD64 on the surface of neutrophils. 

The levels of CD64 surge as the patient's immune response increases.

The researchers tested the device with blood samples from Carle patients in the ICU and emergency room. 

When a physician suspected infection and ordered a blood test, a small drop of the blood drawn was given to the researchers.

The team was able to monitor CD64 levels over time, correlating them with the patient's vital signs. 

"By measuring the CD64 and the white cell counts, we were able to correlate the diagnosis and progress of the patient - whether they were improving or not," said first author of the study Umer Hassan from the University of Illinois at Urbana-Champaign.