A new faster, cheaper and more accurate handheld tool for diagnosing even mild cases of asthma using just a single drop of blood has been developed.
The technology - which takes advantage of a previously unknown correlation between asthmatic patients and the most abundant type of white blood cells in the body - means doctors could diagnose asthma even if their patients are not experiencing symptoms during their visit to the clinic.
Researchers at University of Wisconsin-Madison used neutrophil cell function in a clinical study to show accurate asthma diagnosis.
"What we've done in this paper is presented data that neutrophil cell function in some cases can predict - and in this case actually predicted and measured - whether someone is asthmatic or not," said David Beebe, a UW-Madison professor of biomedical engineering and co-author on the research paper.
"This is one of the first studies to show that this process could actually work in a cheap, easy and practical way," said Beebe.
Asthma remains a very difficult disorder to accurately diagnose, researchers said.
Currently, asthma diagnosis consists of a series of clinical tests, often heavily informed by lung functionality tests.
"They'll measure how much air you can take in, and they'll measure different chemical components of the respired air," Beebe said.
Many of the current tests for diagnosing asthma rely at least partially on the patient experiencing symptoms during or close to their physician visit.
To directly diagnose asthma, Beebe and his team focused on the cell function of neutrophils. Neutrophils are the most abundant white blood cell in the body and generally are the first cells to migrate towards inflammation.
The human body emits chemical signals in response to inflammation or wounds and the neutrophils detect those chemical signals and migrate to the site of the wound to aid in the healing process.
Researchers can track the velocity at which the neutrophil cells migrate - the chemotaxis velocity - to differentiate nonasthmatic samples from the significantly reduced chemotaxis velocity of asthmatic patients.
The team developed the kit-on-a-lid-assay (KOALA) microfluidic technology, which allows them to detect neutrophils using just a single drop of blood.
Using simple lids and bases (each being a small, cheap piece of plastic), diagnosticians place a KOALA lid containing a chemical mixture onto the base containing the blood sample.
That chemical mixture triggers neutrophil migration - and researchers can automatically track and analyse the neutrophil chemotaxis velocity using custom software.
The finding was published in the journal PNAS.
