When you need to measure white blood cell counts, it usually involves trips to clinics and expensive equipment for analysis. Likewise, checking water quality for contaminants can be a lengthy process. 

But now Tufts researchers are coming up with ways to do some of these tests that greatly lowers cost and makes them more widely available. They are using something ubiquitous: paper. Their innovative paper-based tests for monitoring personal health and environmental safety eliminate the need for expensive laboratory equipment, and can be conducted by anyone, anywhere.

Known as paper analytical devices, they can be manufactured cheaply, stored for long periods of time, distributed for use in remote areas, and used to collect critical information when and where it is needed the most. They also each represent a technology platform that can be extended to measure other markers for health and the environment. 

Take one of the most vital measurements in health care: the blood cell count. Measuring white blood cells alone gives clues to everything from infections to autoimmune disease to cancer. Although sample collection—a blood draw—seems simple, it requires a visit to a clinic and access to centralized clinical laboratories for analysis. Large populations of people—those who are homebound or live in remote locations—do not have that access.

Charlie Mace, associate professor of chemistry, thought of a way to help. He and his team created a paper device called a patterned dried blood spot card, in which the paper is engineered with channels and collection zones that measure out defined volumes of blood and allow it to dry in place for later analysis. 

All users need to do is collect blood at home with a finger prick and mail the sample to a lab, which measures the amount of DNA that is unique to the white blood cells, and indicates the number of cells present.