Medical Device Daily

In the continuing evolution of the use of biological markers for diagnosing disease, a New Mexico company has developed a prototype device that it says is able to determine the presence of diabetes, or even pre-diabetes, simply by shining a light on the skin.

Researchers reported on the new technology – specifically, a device called Scout – at the 66th annual scientific sessions of the American Diabetes Association (ADA; Alexandria, Virginia), which wraps up today in Washington. Scout uses fluorescent light to detect the presence of abnormal concentrations of diabetes-related biological markers found in skin. It is able to significantly outperform fasting plasma glucose (FPG) as a screening test for pre-diabetes and Type 2 diabetes, according to study results reported at the ADA meeting.

The data presented showed that the prototype medical device using the technology was able to identify 20% more patients with Type 2 diabetes or its precursor. The study was conducted by researchers from the University of New Mexico School of Medicine, TriCore Reference Labs, InLight Solutions and VeraLight (all Albuquerque, New Mexico), developer of the technology.

John Maynard, vice president of product development for VeraLight, told Medical Device Daily that the company expects to launch clinical trials of the device this time next year, with FDA submission by summer's end 2007, with hoped-for 510(k) clearance in December 2007.

Maynard said the VeraLight Scout, weighing in at about 10 pounds, is about the size of an oversized laptop.

The system uses proprietary fluorescence spectroscopic technology that does not require patient fasting. The subject inserts the palm-side of the forearm into the system, which resembles a drugstore blood-pressure monitor. Over about a minute Scout shines various wavelengths of light on the skin to stimulate fluorescence that is measured to provide an indication of diabetes risk based on the presence of so-called advanced glycation endproducts (AGEs).

The company says that studies have shown that the presence of AGEs, found in skin, correlate well with diabetes and are a predictor of the disease's serious complications.

Analogous to a “diabetes odometer,” AGEs are, VeraLight says, a sensitive metric for the cumulative damage the body has endured due to the effects of abnormally high blood sugar. They affect the proteins that make up blood vessels, connective tissue and skin, and are thought to be major factors in aging and age-related chronic diseases.

It says that such noninvasive skin detection of AGEs could replace the fasting plasma glucose test as the “medical workhorse” for screening for diabetes.

In action, the instrument optically calibrates for skin pigmentation so that performance is not diminished by skin coloration. A fiber-optic probe couples the excitation light to the subject and relays resulting skin fluorescence to a detection module. The system's software utilizes multivariate statistical techniques that are applied to the spectra to obtain a diabetes risk score.

The device includes a cradle, which holds the subject's arm still while it is being optically scanned, Maynard explained. Entered into the computer are the patient's age and a patient identifier to allow for tracking of results. Then, to get the reading, the user simply pushes a button, and within a minute, a diabetes risk score – ranging from 0 to 100 – is provided.

“A reading above 54 is considered abnormal,” and should be further investigated with a glucose tolerance test, Maynard said. He noted also that “the higher the number above 54, the more likely you are to have diabetes or pre-diabetes.”

“If you order the fasting glucose as a follow-up, it's likely that it would disagree [with our results], because the fasting glucose test is a less sensitive test,” Maynard said.

AGEs “have been well-recognized as a diabetes biomarker and as a predictor of complications that may lead to blindness and kidney disease,” said Robert Ratner, MD, vice president of scientific affairs at Medstar Research Institute (Hyattsville, Maryland), which calls itself the Baltimore/Washington area's largest healthcare delivery system.

“Until the advent of VeraLight's technology and the Scout system, a skin biopsy was the only way to detect AGEs which made them impractical for clinical use. . . Skin AGEs will be a valuable tool for identifying people with sub-clinical disease. Lack of a fasting requirement, overall convenience and superior accuracy may make this the technology of choice for diabetes and pre-diabetes screening.”

The study reported on at ADA was undertaken in 328 subjects at risk for diabetes or pre-diabetes to evaluate the Scout against the FPG test, which measures a patient's blood sugar after a 12-hour fast. The oral glucose tolerance test, which measures blood glucose two hours after oral administration of a 75-gram glucose load, was used as a confirmatory test. The subjects in the study ranged in age from 21 to 88.

The results were analyzed to compare each test's “receiver-operator characteristics” – a statistical measure that graphically illustrates a test's false-positive relationship to sensitivity (a measure of true positives).

At the lower, impaired fasting glucose threshold of 100 milligrams per deciliter (mg/dl), the FPG sensitivity was 57.5% with a specificity (a measure of true normals) of 78%. At that specificity, the Scout sensitivity was 68.9%, showing the ability to detect 20% more individuals with diabetes or its precursor.

VeraLight argues that due to their “inaccuracy and inconvenience,” current screening methods for diabetes are grossly inadequate, with the result that 50% of those with diabetes are not identified until they present five to 10 years into the disease with one or more, often irreversible complications.

Thus, it is promoting the Scout system as a more accurate and convenient screening method which could “dramatically reduce the costs and morbidity associated with such complications, allowing patients to halt or reverse disease progression.”

In 2002 the U.S. spent $132 billion on diabetes treatment and complications, about 10% of all national healthcare expenditures, according to VeraLight. Most of this, the company said, was for complications, and that “numerous clinical studies” have demonstrated the effectiveness of early therapeutic intervention in preventing the disease or mitigating these complications.