Engineers at Columbia University have developed a low-cost smartphone accessory for rapid diagnosis of infectious diseases at point of care.

The device can perform a point-of-care test that simultaneously detects three infectious disease markers from a finger prick of blood in just 15 minutes. It replicates, for the first time, all mechanical, optical, and electronic functions of a lab-based blood test.

"Our work shows that a full laboratory-quality immunoassay can be run on a smartphone accessory," Samuel Sia, who led the project, said in a statement. "Coupling microfluidics with recent advances in consumer electronics can make certain lab-based diagnostics accessible to almost any population with access to smartphones. This kind of capability can transform how health care services are delivered around the world."

Sia's innovative accessory or dongle, a small device that easily connects to a smartphone or computer, was recently piloted by health care workers in Rwanda who tested whole blood obtained via a finger prick from 96 patients who were enrolling into prevention-of-mother-to-child-transmission clinics or voluntary counseling and testing centers.

Sia's team wanted to build upon their previous work in miniaturizing diagnostics hardware for rapid point-of-care diagnosis of HIV, syphilis, and other sexually transmitted diseases.

"We know that early diagnosis and treatment in pregnant mothers can greatly reduce adverse consequences to both mothers and their babies," Sia notes.

 The team developed the dongle to be small and light enough to fit into one hand, and to run assays on disposable plastic cassettes with pre-loaded reagents, where disease-specific zones provided an objective read-out, much like an ELISA assay. Sia estimates the dongle will have a manufacturing cost of $34, much lower than the $18,450 that typical ELISA equipment runs.

Sia collaborated with researchers from Columbia's Mailman School of Public Health; the Institute of HIV Disease Prevention and Control, Rwanda Biomedical Center; Department of Pathology and Cell Biology, Columbia University Medical Center; Centers for Disease Control and Prevention--Laboratory Reference and Research Branch, Atlanta; and OPKO Diagnostics.

 The work is published Feb. 4 in Science Translational Medicine.