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 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".
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."