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Handheld Device Uses Blood Sample to Distinguish Asthma From Allergies

Researchers track chemotaxis velocity

Using just a single drop of blood, researchers at the University of Wisconsin–Madison have developed a new tool for diagnosing even mild cases of asthma.

The researchers used neutrophil cell function in a clinical study to show accurate asthma diagnosis.

The handheld technology — which takes advantage of a previously unknown correlation between asthmatic patients and the function of neutrophil cells — means that doctors could diagnose asthma even if their patients are not experiencing symptoms during their visit.

The team described its findings in the April 7 online issue of the Proceedings of the National Academy of Sciences.

Many of the current tests for diagnosing asthma rely at least partially on the patient experiencing symptoms during or close to their physician visit, the authors say. In addition, all of the diagnostic tests require the patient’s compliance, which can make diagnosis difficult in the elderly or in children.

To directly diagnose asthma, Dr. David Beebe and his colleagues focused on the cell function of neutrophils, which generally are the first cells to migrate toward inflammation.

According to Beebe, the human body emits chemical signals in response to inflammation or wounds. 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.

Traditionally, a clinical study of neutrophils required so much blood work, specialized equipment, and processing that it was impractical to use in diagnostics, Beebe explains. However, students at UW–Madison developed the kit-on-a-lid assay (KOALA) microfluidic technology, which allows them to detect neutrophils using just a single drop of blood.

The KOALA diagnostic procedure is simple, Beebe says. Using simple lids and bases (each consisting of a small, inexpensive 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 analyze the neutrophil chemotaxis velocity using custom software.

Beebe emphasizes that by using the KOALA lids containing pre-mixed chemicals, the diagnostic procedure is scalable, inexpensive, quick, and repeatable.

“The KOALA platform represents the next-generation biomedical research kit,” he says. “Instead of getting a box of media and staining solution and having to do a lot of manual manipulation, you would get the base for the fluid sample [and] the prepackaged KOALA lids, and to do any testing, [you] just place a lid (or series of lids) on the base.”

Source: Phys.Org; April 8, 2014.

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