The moment the zookeepers had been waiting for came yesterday when Mei Xiang left her cub for a leisurely breakfast in the next room.

"The door is closed," Lisa M. Stevens, the National Zoo's assistant curator, said in a phone call summoning the zoo's veterinarian.

With that, Stevens and keeper Laurie Perry swooped in and snatched up the baby panda long enough to determine that it is male and weighed 1.82 pounds. By the time Mei Xiang waddled back to the cub, somewhat anxiously, after a bamboo meal, a drink of water and a bathroom break, her newborn was back where she had left it.

The examination, which Associate Veterinarian Sharon L. Deem joined, took nine minutes. It was the first time since the cub's birth July 9 that a person had handled it or seen it up close. Until then, the rare creature could be viewed only through cameras in the den that also are connected to the Internet.

In China, captive panda cubs are examined soon after birth, but National Zoo officials decided to wait until Mei Xiang seemed comfortable leaving her newborn alone. Yesterday, shortly after 8 a.m., as Mei Xiang lingered over her bamboo, they made their move. Stevens noticed approvingly that Mei Xiang did not react when the door clanged shut, separating her from her cub.

While Deem was driving the short distance from the veterinary hospital, Stevens and Perry put on green protective gloves and medical gowns and went into the den.

"Oh, my God," Perry said as she stood over the cub, preparing to pick it up and put it into a small plastic box lined with fleece, Stevens recalled later. Perry carried the cub-in-a-box to the now-closed public viewing area, where they had set up a table outfitted with examination gear, blank data forms and cheat-sheet photographs of panda genitalia.

They worked off a list: Weigh first. Determine sex. "We looked at it and said, 'It looks like a boy,' " Stevens said. "Then we started taking pictures."

Stevens scanned the cub as she worked, noticing that the umbilical cord area looked good. The cub had no redness, no wounds, no discharge on its body. "It's just a cute little, fat, clean little cub," she said.

Deem arrived and agreed it was male. She listened to the heart, detecting no murmur. She thought the lungs sounded good. She gently handled the small body, finding no hernias or lumps. There was no crust around the eyes, which probably will not open for another week or two. The pinkish skin, still visible through the rapidly arriving black and white fur, looked healthy.

"I was really impressed with how sturdy this little fellow was -- like a little rugby player," Deem said. "He felt a good size."

Throughout, Stevens said, the cub was quiet, its arms and legs splayed out. Then Deem put her finger in its mouth, to check the gums, and the cub squawked. "Maybe he thought it was a nipple coming in," she joked later.

Their last task was to measure from nose to tail: 12 inches. They finished quickly, Stevens said, because they could tell Mei Xiang was anxious.

She was standing on her hind legs at the door to the den, pawing at it. Had she turned to her right and looked through the glass to the public viewing area, she would have seen her cub being examined, but she did not. Stevens described the mother panda as having "minor anxiety. It wasn't like she was traumatized or anything."

Stevens and Deem said they needed to examine the cub to make sure it had no health problems and to add the statistics to data being collected worldwide about captive panda development in hopes of improving their endangered status in the wild.

Pandas are celebrity entertainers for zoos, but the U.S. Fish and Wildlife Service permits them in this country only if they are part of a research program. Mei Xiang and her mate, Tian Tian, came to the zoo in 2000 on a 10-year loan from China, in exchange for $10 million in privately raised funds that underwrite conservation programs in that country.

Exam over, Deem carried the "precious little baby" back to its den, cradled against her chest. "He wasn't fussing," she said. "He was just riding."

They retreated from the room and opened the door to let Mei Xiang in, wondering what she would do but not concerned that she would hurt or reject her offspring, Stevens said.

The mother panda, who turned 7 last month, quickly retrieved and then closely examined her cub. Then she enclosed it in her huge paw, turned over and went to sleep.

"I can't believe it was nine minutes," Stevens said of the exam. "It felt like three."

Veterinarian Sharon L. Deem, left, and Assistant Curator Lisa M. Stevens study the panda cub during his first health evaluation.