TIVERTON — Chester the yellow lab had not been in Tiverton for 24 hours before he sounded the alarm.

The dog’s new owner, John Mellekas, was in his Durfee Road living room when Chester began tapping him below the knee insistently.

That is what Chester’s diabetes detection training has taught him to do when he senses something amiss in his handler’s blood sugar level.

John checked, “and sure enough, it was low. I went and got a drink of orange juice.”

Not just low, really low, added Ed Peeples.

Mr. Peeples is the owner of Las Vegas, Nevada-based Diabetes Alert Dogs of America and had flown here to deliver Chester along with another of his firm’s dog trainers, Nicole Parayno.

John’s blood sugar level was hovering around 40 — far below the 75 or so that it should have been.

“That is serious,” Mr. Peeples said. “At 30 he’d be on the floor and we would be dialing 911.”

The problem is that, having had Type 1 diabetes for 50 years, Mr. Mellekas now finds it difficult to tell when his blood sugar levels are off.

Asked if he’d realized his level had been so low, he replied, “Not really.” He said the best he can describe the sensation of trouble is that “it feels like you are climbing a mountain and just can’t take another step.”

For his warning Chester was rewarded with a handful of dog treats. “It’s actually the second time he’s helped me this way since he arrived yesterday,” Mr. Mellekas said.

Chester, now 18 months old, has been training for this moment for most of his life, Mr. Peeples said. And the training must continue to keep the dog sharp.

In his freezer, Mr. Mellekas now keeps cotton saliva swabs, some of which were taken when his blood sugar was too high, some when it was too low, and some when it was normal. Chester must take a sniff and, if he alerts correctly, will get a treat. This should happen five times every day.

Chester wasted no time making friends in Rhode Island.

Just hours after his arrival, he and John were the guests of honor at a fund raiser hosted by O’Brien’s Pub in Newport. Friends there raised $3,500, an outcome that leaves him now about 75 percent of the way toward covering his dog’s $15,000 price tag.

The dogs are expensive, Mr. Peeples said, because of the countless hours of training each receives. “Events like this are the only way many people can afford them … I’m always amazed to see how many people are willing to help. John obviously has a lot of good friends around here.”

His next public appearance was to be that Friday noon lunch at the Tiverton Senior Center.

Mr. Mellekas is a regular for lunch there “and I can’t wait to introduce him … People there have been looking forward to this.”

Chester’s status as an assistance dog gets him in just about every place (by law). John carries paperwork identifying Chester and Chester has a red vest that he can wear.

Mr. Peeples said the two seem an ideal match.

At the start of the process, Mr. Mellekas answered a long list of questions aimed at identifying his personality traits and the sort of surroundings to which the dog would need to fit.

He’s not as active as he was during his 25 years as superintendent at the Newport Tennis Hall of Fame so the aim was to match him with a puppy suited to a quieter lifestyle.

“He’s low-key, mellow — a lot like John,” Mr. Peeples said.

That was evident at O’Brien’s Pub where Chester patiently obliged children’s hugs, applause and loads of attention without ever losing his cool.

Mr. Mellekas has also taken Chester for a first few walks around the neighborhood. He calmly made the acquaintance of one neighbor dog. “I bet he’ll like the fact that it’s not 115 degrees outside here in Tiverton, Mr. Peeples said.

The key to success in these relationships is all in finding the right dog and the preparation, the trainer said. And followup. “It’s important that John keep the training up — we are always available to answer questions or offer suggestions.” If need be they’ll even fly out to address a more serious issue (Mr. Mellekas would have to cover the airfare).

Diabetes Alert Dogs of America placed 65 dogs in its first year, Mr. Peeples said; this year the total will be over 100.

Mr. Mellekas’ GoFundMe site can be found at —