New blood test 'can detect risk of infection in minutes'

Scientists have created a device that is able to detect a person's risk of infection from a drop of blood within minutes, as opposed to current methods, which can take up to 2 hours. This is according to a study published in the journal Technology.

One common laboratory test to determine an individual's risk of infection is the counting of neutrophils in the blood, known as absolute neutrophil count.

Neutrophils are a type of white blood cell found in human blood. These are the "body's first line of defense" against inflammation and infection.

Within minutes of detecting infection, the neutrophils flee from the blood toward tissue, where they settle at the sites of infection.

"If neutrophils do not migrate well and cannot reach inside the tissues, this situation could have the same consequences as a low neutrophil count".

With this in mind, the investigators created a "miniaturized silicone-based device" that they say is able to measure migration patterns of neutrophils from a finger prick of blood, and this can be carried out within a matter of minutes.

The researchers say that methods currently used to measure the functions of neutrophils involve separating them from the blood. This process can take 2 hours, and the investigators say that the procedure needs to be conducted by skilled laboratory personnel. This, however poses a problem within clinical conditions, such as treating cases of patients with burn injuries, as the process is time-consuming and medical professionals' priorities change throughout the day.

"To address the need for rapid and robust assays, a microfluidic device was designed that measured neutrophil chemotaxis directly from a single droplet of blood.

By comparing neutrophil chemotaxis from finger prick, venous blood and purified neutrophil samples, it was found that average velocity of (19 ± 6 μm/min) and directionality (91.1%) between the three sources was consistent."

Hence it was concluded that being able to measure patients' risk of infections in a matter of minutes from only a droplet of blood is a "significant improvement and one that will improve current treatment."