On Tuesday nights at D4D, dogs and their potential handlers test the waters with one another. People are focused and hopeful as they learn how to handle a dog and what to expect in public when accompanied by a service dog. Meanwhile, staff members are on the lookout for a special connection. “Many people are eager to be partnered with one of our dogs,” says director Carol Edwards. “But we don’t make placements according to a waiting list; instead, we pair up dogs and people when we see a special chemistry at work.” Once a match has been made, the dog and his handler work as a leashed-together pair 24 hours a day for up to two months. During this “umbilical period,” the dog learns to connect his person’s hypoglycemic scent with a reward. Reynolds explains, “It’s almost as if they are saying, I smell the scent. I’m going to let you know that I smell the scent, and then I’ll get treats!
 
At first, Harris didn’t believe that a dog could detect low blood sugar, but her skepticism vanished when she worked at a camp for diabetic children and accompanied a D4D dog on his midnight rounds. She became a believer when she watched the dog alert his handler to a sleeping child whose blood sugar reading was in the low 30s.
 
Just three weeks before the momentous night—the night when she didn’t wake up freezing in sweat-soaked linens—Harris brought Destiny home. Instead of ravenously raiding the refrigerator and experiencing the disorientation and emotional rollercoaster that accompanies midnight hypoglycemia, she simply lay in bed and drank a glass of juice. “It’s the best low I’ve ever had,” she confesses with a smile.
 
These days, Destiny accompanies Harris everywhere, wearing the blue vest that identifies her as a medical-alert service dog. Destiny’s presence in the car eliminates Harris’s concern about going low while driving, and in the classroom, Destiny sits by Harris’s side and gives her enough warning that she can grab a healthy snack without missing a moment of instruction. And at night, this faithful companion frees Harris to sleep soundly without the risks and fears of nighttime hypoglycemia.
 
The work at D4D holds promise for hundreds of thousands of Type 1 diabetics. For Mark and the other tireless volunteers at D4D, the bottom line is that these dogs relieve people of the fear of hypoglycemia, and they save lives. Most rewarding are the phone calls from parents who say, “The dog woke me up last night, and my child’s blood glucose was 40.”
 
Harris grew up with Lab mixes, and initially she looked forward to building a special relationship with her new dog; then she realized exactly how special that relationship would be: “When I first received Destiny, I was so excited to be able to care for a dog. This is really cool! I thought to myself. She depends on me for fun, for play, for food, for a good walk. But when she started to alert on me, it really struck home: I am the one who depends on her to literally save my life.” No glucose meter in the world can measure the depth of that bond.

Originally published as “An Immeasurable Bond.”