Smartphone Attachment Rapidly Determines Urine Albumin Level and Transmits the Result

The potential value of smartphone applications in the field of in vitro diagnosis (IVD) has been emphasized by the development of a smartphone attachment that rapidly determines the level of albumin in a patient's urine and transmits the results to a database or healthcare center.

The light-weight (approximately 148 grams) and compact Albumin Tester attachment developed by investigators at the University of California, Los Angeles (USA) is mechanically installed on the existing camera unit of a smartphone, where test and control tubes are inserted from the side and are excited by a battery powered laser diode.

The excitation beam, after probing the urine sample in the test tube, interacts with the control tube, and the resulting fluorescent emission is collected perpendicular to the direction of the excitation, where the smartphone camera captures the images of the fluorescent tubes through the use of an external plastic lens that is inserted between the sample and the camera lens.

The acquired fluorescent images of the sample and control tubes are digitally processed within one second through an Android application running on the same smartphone for quantification of albumin concentration in the urine specimen. Test results are then transmitted by the smartphone to a database or healthcare provider.

A study published in the August 9, 2013, online edition of the journal Lab on a Chip revealed that by following a simple sample preparation approach, which took about five minutes per test (including the incubation time), the investigators demonstrated that the detection limit of the sensing platform was five to 10 micrograms per milliliter (which is more than three times lower than clinically accepted normal range) in buffer as well as urine samples.

The investigators suggested that an automated albumin-testing tool running on a smartphone could be useful for early diagnosis of kidney disease or for monitoring of chronic patients, especially those suffering from diabetes, hypertension, and/or cardiovascular diseases.

"Albumin testing is frequently done to assess kidney damage, especially for diabetes patients," said senior author Dr. Aydogan Ozcan, professor of electrical and bio-engineering at the University of California, Los Angeles. "This device provides an extremely convenient platform for chronic patients at home or in remote locations where cell phones work."

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University of California, Los Angeles