The evolution of diabetes testing: Q&A with Paul Yip
Today, diabetics can accurately measure their blood glucose in seconds with light, portable devices. But testing wasn’t always this easy or trustworthy. Paul Yip, a professor in U of T’s Department of Laboratory Medicine and Pathobiology, has a passion for point-of-care testing, including blood glucose meters. As a clinical biochemist, Yip ensures the quality of laboratory testing at the University Health Network. He spoke to writer Katie Babcock about how diabetes testing has evolved to become more accurate and reliable, and how it will continue to empower millions of people in the future. He also developed an infographic on the evolution of diabetes testing.
Why is it so important for diabetics to monitor their blood-glucose levels accurately?
If you have diabetes, it means you have too much glucose in your blood. Symptoms include increased thirst, frequent urination and increased hunger.
The Public Health Agency of Canada predicts that the number of Canadians with diabetes will reach 3.7 million by 2018. As you can see, many Canadians are dealing with this disease. Careful monitoring can prevent complications including heart and kidney disease, blindness and amputation.
How did doctors first diagnose diabetes?
Diabetes was first identified as early as 1500 BC, and in 600 BC physicians recorded that ants were attracted to sugar in patients’ urine. This sounds unusual now, but during the Middle Ages, doctors used uroscopy, a practice where they studied urine to diagnose medical conditions. They consulted intricately designed urine flavour charts that described the sight, smell and taste of urine. The one disease that they diagnosed correctly was diabetes because of the sweet taste of patients’ urine.
In 1674, an English doctor named Thomas Willis described diabetics’ urine as “wonderfully sweet as if it were imbued with honey or sugar.” He then added “mellitus” to diabetes, meaning honey in Latin.
Why did devices evolve to measure blood instead of urine glucose?
Measuring blood glucose measures the actual levels in a person rather than estimating with urine glucose. The Ames Reflectance Meter was the first blood glucose meter, and it electronically analyzed test strips using light. This device reduced the subjectivity of looking at colour and results became consistent.
About 20 years later, the next big technological jump was moving from the reflectance meter to electrochemical devices. These meters used biosensors to analyze glucose more specifically — there are lots of sugars in the blood and this technology zeroed in on the important one for diabetes. Over time, testing required less blood and became more accurate and reliable. At the end of the day, patients could do a better job of self-managing their blood sugar levels.
Where is diabetes monitoring heading in the future?
It’s really amazing to see where technology is headed. Currently, Google has developed a contact lens that detects glucose in tears. This has a long way to go before clinical trials, but it seems like an interesting possibility. There’s also the artificial pancreas, which is in clinical trials at the moment and has proven to be successful so far. It includes a glucose monitor that automatically signals a pump to deliver insulin. This system reduces human error and ultimately improves patient outcomes.
Why are you interested in the evolution of diabetes testing?
As a clinical biochemist, I’m interested in how we can use diagnostics to help patients take control of their disease. The laboratory can seem like a black box because patients aren’t quite sure what happens to their samples. Yet the role of the lab is critically important — up to 70 per cent of all medical decisions are based on lab tests.
My current interest includes point-of-care testing, which is testing that’s done at the patient’s bedside or at home. It’s all about empowering and educating patients to keep them safe and to enhance their quality of life.
