A recall of potentially deadly pet food has dog and cat owners studying their animals for even the slightest hint of illness and swamping veterinarians nationwide with calls about symptoms both real and imagined.

“It’s like we’re on pins and needles,” said Brian Paone, a 27-year-old loan auditor in Knoxville, Tenn., who scheduled a blood test with his vet after realizing both of his cats had eaten brands on the recall list.

“You kind of sit there and wonder — it’s terrible to say this — you wonder if this is going to be your last moments with your pet. It’s not pleasant.”

Some of the 60 million cans and pouches of food have been blamed for kidney failure in scores of animals and killed at least 16 pets. Neither the manufacturer nor authorities have been able to determine why the pets died.

Atlanta veterinarian Will Draper received so many calls and e-mails about the recall that he drafted a newsletter on it and e-mailed his customers.

“That helped tremendously,” Draper said. “It has calmed clients.”

Since Friday, nearly 100 brands of the “cuts and gravy” style food have been recalled by Menu Foods of Canada, including popular labels sold at Wal-Mart, Kroger and other large retailers.

Veterinarians are directing most questions to the Food and Drug Administration’s recall Web site. Some have agreed to run blood tests on pets, even though many of the animals have not consumed any of the recalled brands.

Pet owners with animals showing symptoms such as vomiting, lethargy and extreme thirst are being told to bring them in for immediate examination.

“The recall is huge. It’s unprecedented, and people are seeing their dog food is on the list and picking up the phone, wondering if there’s anything they can do or what to do,” said Tim Hackett, who runs a small-animal clinic at Colorado State University in Fort Collins. “Fortunately, most of these animals are absolutely fine.”

Julie Benesh of Chicago brought her cat, Truffle, to a vet’s office Wednesday after realizing the animal had eaten some of the contaminated food. The cat was lethargic and had been drinking an unusual amount of water.

“That’s my baby,” Benesh said of the black-and-white cat she’s had since the animal was a kitten. “We’ve been through a lot together.”

The Animal Medical Center on the East Side of Manhattan has tested 143 animals for renal failure since Saturday. Of those, 10 were confirmed to be diet-related cases, and one cat died.

“I have people coming in who haven’t even said their pet’s eaten the bad food, but they’re worried that maybe the recall has not been broad enough so they want their pet tested to be sure,” said Ann Hohenhaus, a veterinarian at the clinic.

Los Angeles County officials have confirmed at least nine cases of kidney failure in dogs and cats exposed to the recalled food, said Jonathan Fielding, county director of public health.

The recall has led to at least three lawsuits against Menu Foods from pet owners who allege their animals got sick or died after eating recalled food.

Menu Foods CEO and President Paul Henderson said Wednesday that the company is still investigating the cause of the kidney failure because the food linked to the deaths has shown no signs of contamination. He apologized for the worry that the recall has caused.

Denise Tracy of Milford, Mass., said her first thought after hearing about the recall was, “Oh my gosh, I killed my cat.” Fluffy’s health deteriorated after Tracy fed her Special Kitty brand food, one of the recalled labels, and she had to euthanize the 11-year-old cat last week.

She said the family, including her five children, are heartbroken. Her husband contacted a lawyer, and she plans to contact her state’s attorney general.

“They’re killing animals because of somebody’s mistake,” Tracy said. “They should be held accountable for that.”

In California, a Yorkshire terrier named Pebbles has been battling kidney failure since eating Nutro dog food. Even hooked to an IV, she attempts to wag her tail. The dog’s owner, Jeff Kerner, said he has called and e-mailed Nutro, and hasn’t heard back.

“I want to give them an opportunity to do the right thing. Money can only do one thing, which is pay bills,” Kerner said. “I don’t want to end up with my dog not surviving and then owe $10,000. Or that she survives and I owe $10,000.”

The FDA has sent inspectors to Menu Food plants in New Jersey and Kansas. Most complaints stem from products made at the latter factory, though both received shipments of wheat gluten, identified as a possible source of contamination, from the same supplier, said Stephen F. Sundlof, the FDA’s chief veterinarian.

The ingredient is a protein source used to thicken the pet food gravy.